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		<h1>Chuyên đề số nguyên nâng cao</h1>
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			<li>Thứ bảy - 31/07/2021 16:13</li>
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			<div class="Section1"><img alt="" height="1449" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-1.jpeg" width="1024" /><span style="page:Section1"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page1"></a></span></span></span></div>

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<div class="Section2"><span style="page:Section2"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page2"></a><span style="font-size:15.5pt">HƯỚNG DẪN SỬ DỤNG SÁCH</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:133%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:133%">Bạn đang cầm trên tay cuốn sách tương tác được phát triển bởi Tilado®. Cuốn sách này là phiên bản in của sách điện tử tại http://tilado.edu.vn.</span></span></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Để có thể sử dụng hiệu quả cuốn sách, bạn cần có tài khoản sử dụng tại Tilado®.</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Trong trường hợp bạn chưa có tài khoản, bạn cần tạo tài khoản như sau:</span></span></span></span><br />
&nbsp;
<ol>
	<li><span style="page:Section2"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Vào trang http://tilado.edu.vn</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2">
	<li style="margin-right:24px"><span style="page:Section2"><span style="font-size:11pt"><span style="line-height:100%"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:100%">Bấm vào nút &quot;Đăng ký&quot; ở góc phải trên màn hình để hiển thị ra phiếu đăng ký.</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3">
	<li style="margin-right:28px"><span style="page:Section2"><span style="font-size:11pt"><span style="line-height:100%"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:100%">Điền thông tin của bạn vào phiếu đăng ký thành viên hiện ra. Chú ý những chỗ có dấu sao màu đỏ là bắt buộc.</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="4">
	<li style="margin-right:7px; text-align:justify"><span style="page:Section2"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:100%"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:100%">Sau khi bấm &quot;Đăng ký&quot;, bạn sẽ nhận được 1 email gửi đến hòm mail của bạn. Trong email đó, có 1 đường dẫn xác nhận việc đăng ký. Bạn chỉ cần bấm vào đường dẫn đó là việc đăng ký hoàn tất.</span></span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="5">
	<li><span style="page:Section2"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Sau khi đăng ký xong, bạn có thể đăng nhập vào hệ thống bất kỳ khi nào.</span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section2"><span style="font-size:11pt"><span style="line-height:162%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:162%">Khi đã có tài khoản, bạn có thể kết hợp việc sử dụng sách điện tử với sách in cùng nhau. Sách bao gồm nhiều câu hỏi, dưới mỗi câu hỏi có 1 đường dẫn tương ứng với câu hỏi trên phiên bản điện tử như hình ở dưới.</span></span></span></span></span></span><br />
<img alt="" height="65" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-2.jpeg" width="380" /><br />
<span style="page:Section2"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:196%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:196%">Nhập đường dẫn vào trình duyệt sẽ giúp bạn kiểm tra đáp án hoặc xem lời giải chi tiết của bài tập. Nếu bạn sử dụng điện thoại, có thể sử dụng QRCode đi kèm để tiện truy cập.</span></span></span></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cảm ơn bạn đã sử dụng sản phẩm của Tilado®</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tilado®</span></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section3"><span style="page:Section3"><span style="font-size:11pt"><span style="line-height:112%"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page3"></a><span style="font-size:31.5pt"><span style="line-height:112%">I. CÁC PHÉP TOÁN TRONG TẬP SỐ NGUYÊN</span></span></span></span></span></span><br />
<img alt="" height="5" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-3.jpeg" width="807" /><br />
<br />
<br />
<br />
<span style="page:Section3"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:21.0pt">CỘNG CÁC SỐ NGUYÊN</span></span></span></span><br />
&nbsp;
<ol>
	<li><span style="page:Section3"><span style="font-size:11pt"><span style="line-height:207%"><span style="tab-stops:16.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:207%">Trong tháng 3 Hà Nội chặt 1568 cây xanh. Trong tháng 6 có một cơn lốc làm bật gốc và gãy 1223 cây xanh. Tính số cây xanh bị mất sau hai lần đó.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-4.jpeg" width="99" /><br />
<span style="page:Section3"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a42"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a42</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="2">
	<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:17.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">So sánh:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">|6 + 25| và |6| + |25|</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="2" style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">|(</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">9) + (</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">21)| và |</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">9| + |</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">21|</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-5.jpeg" width="99" /><br />
<br />
<span style="page:Section3"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a52"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a52</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="3">
	<li style="margin-right:29px"><span style="page:Section3"><span style="font-size:11pt"><span style="line-height:175%"><span style="tab-stops:16.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:175%">Tính tổng của số nguyên âm lớn nhất có hai chữ số với số nguyên âm lớn nhất.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-6.jpeg" width="99" /><br />
<span style="page:Section3"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a72"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a72</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="4">
	<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:17.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Điền dấu &quot;&lt;&quot;, &quot;&gt;&quot;, &quot;=&quot; thích hợp vào ô vuông:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">1) + (</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">9)&nbsp;&nbsp; (</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">9)</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="2" style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">22)&nbsp;&nbsp; (</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">3) + (</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">20)</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="3" style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">25&nbsp;&nbsp; 12 + 13</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-7.jpeg" width="99" /><br />
<br />
<span style="page:Section3"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a82"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a82</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="5">
	<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:17.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Điền dấu &quot;+&quot;, &quot;</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">&quot;, thích hợp vào ô vuông:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(&nbsp; 7) + (&nbsp; 3) = </span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">10</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="2" style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(&nbsp; 21) + (&nbsp; 4) = 25</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="3" style="list-style-type:lower-alpha">
		<li><span style="page:Section3"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(&nbsp; 5) + (</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">6) = (&nbsp; 11)</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section4"><span style="page:Section4"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page4"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-8.jpeg" width="99" /><br />
<br />
<span style="page:Section4"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a92"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a92</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="6">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:16.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính giá trị biểu thức:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol style="list-style-type:lower-alpha">
		<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">m + |</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">12| với m = |</span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">33|</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="2" style="list-style-type:lower-alpha">
		<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">|n| + 35 với n = </span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">5</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-9.jpeg" width="99" /><br />
<br />
<span style="page:Section4"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a102"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a102</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="7">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:16.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho a và b là hai số nguyên cùng dấu. Biết |a| + |b| = 10. Tính a + b?</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-10.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section4"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a153"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a153</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="8">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:16.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol style="list-style-type:lower-alpha">
		<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">x + y = |x| + |y| với </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">≥ 0;</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">≥ 0</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="2" style="list-style-type:lower-alpha">
		<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">x + y = </span><span style="font-size:15.5pt"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span><span style="font-size:15.5pt">(|x| + |y|) với x &lt; 0; y &lt; 0</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-11.jpeg" width="99" /><br />
<br />
<span style="page:Section4"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a143"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a143</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="9">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:16.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol style="list-style-type:lower-alpha">
		<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tổng hai số nguyên dương luôn lớn hơn mỗi số đó.</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
&nbsp;

<ol>
	<li style="list-style-type:none">
	<ol start="2" style="list-style-type:lower-alpha">
		<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tổng hai số nguyên âm luôn nhỏ hơn mỗi số đó.</span></span></span></span></span></li>
	</ol>
	</li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-12.jpeg" width="99" /><br />
<br />
<span style="page:Section4"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a132"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a132</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="10">
	<li style="margin-right:264px"><span style="page:Section4"><span style="font-size:11pt"><span style="line-height:127%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:127%">Tìm </span></span><i><span style="font-size:15.5pt"><span style="line-height:127%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:127%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span></span> <i><span style="font-size:15.5pt"><span style="line-height:127%">Z</span></span></i><span style="font-size:15.5pt"><span style="line-height:127%"> bằng cách dự đoán và thử lại: a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:127%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:127%">+ 17 = 23 + 24</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section4"><span style="font-size:11pt"><span style="line-height:148%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:148%">b. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">|</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">| + ( − 5) = ( − 8) + ( − 12)</span></span><span style="font-size:15.5pt"><span style="line-height:148%"> c. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">|</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">| + ( − 14) = ( − 11) + ( − 3)</span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-13.jpeg" width="99" /><br />
<span style="page:Section4"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632a122"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632a122</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="11">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Rút gọn các biểu thức sau:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">A </span></i><span style="font-size:15.5pt">= (71 +<i> x</i>) − ( − 24 −<i> x</i>) + ( − 35 −<i> x</i>)</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section4"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">B </span></i><span style="font-size:15.5pt">=<i> x </i>− 34 − &#91;(15 +<i> x</i>) − (23 −<i> x</i>)&#93;</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section5">
<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section5"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page5"></a><i><span style="font-size:15.5pt">C </span></i><span style="font-size:15.5pt">= ( − 15 + |<i> x </i>| ) + (25 − | −<i> x </i>| )</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-14.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/63252"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/63252</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="12">
	<li><span style="page:Section5"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section5"><span style="font-size:11pt"><span style="line-height:119%"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:119%">Với giá trị nào của số nguyên </span></span><i><span style="font-size:15.5pt"><span style="line-height:119%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:119%"> và </span></span><i><span style="font-size:15.5pt"><span style="line-height:119%">y</span></span></i><span style="font-size:15.5pt"><span style="line-height:119%"> thì tổng </span></span><i><span style="font-size:15.5pt"><span style="line-height:119%">M</span></span></i> <span style="font-size:15.5pt"><span style="line-height:119%">= |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:119%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:119%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:119%">y</span></span></i> <span style="font-size:15.5pt"><span style="line-height:119%">| + |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:119%">y</span></span></i> <span style="font-size:15.5pt"><span style="line-height:119%">+ 2 | + 2005</span></span><span style="font-size:15.5pt"><span style="line-height:119%"> đạt giá trị nhỏ nhất?</span></span></span></span></span></span></span></li>
	<li style="margin-right:8px"><span style="page:Section5"><span style="font-size:11pt"><span style="line-height:112%"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:112%">Cho </span></span><i><span style="font-size:15.5pt"><span style="line-height:112%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span></span> <i><span style="font-size:15.5pt"><span style="line-height:112%">Z</span></span></i><span style="font-size:15.5pt"><span style="line-height:112%">. Tìm </span></span><i><span style="font-size:15.5pt"><span style="line-height:112%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:112%"> để biểu thức </span></span><i><span style="font-size:15.5pt"><span style="line-height:112%">A</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%">= 1000 − |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:112%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%">+ 5 |</span></span><span style="font-size:15.5pt"><span style="line-height:112%"> có giá trị lớn nhất. Tìm giá trị lớn nhất đó.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-15.jpeg" width="99" /><br />
<span style="page:Section5"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632242"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632242</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="13">
	<li><span style="page:Section5"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm </span><i><span style="font-size:15.5pt">x</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span> <i><span style="font-size:15.5pt">Z</span></i><span style="font-size:15.5pt"> biết </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">+ 45 − 40 | + |</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">+ 10 − 11 | ≤ 0</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-16.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632232"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632232</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="14">
	<li><span style="page:Section5"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">&lt;</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">&lt; 0</span><span style="font-size:15.5pt"> và </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">| − |</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">| = 100</span><span style="font-size:15.5pt">. Tính </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">y</span></i></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-17.jpeg" width="99" /><br />
<br />
&nbsp;
<table class="Table" style="border-collapse:collapse">
	<tbody>
		<tr>
			<td style="width:32px; padding:0in 0in 0in 0in; height:24px" valign="bottom">&nbsp;</td>
			<td style="width:7px; padding:0in 0in 0in 0in; height:24px" valign="bottom">&nbsp;</td>
			<td style="width:33px; padding:0in 0in 0in 0in; height:24px" valign="bottom">&nbsp;</td>
			<td colspan="2" style="width:293px; padding:0in 0in 0in 0in; height:24px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span></td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:24px" valign="bottom">&nbsp;</td>
		</tr>
		<tr>
			<td style="width:32px; padding:0in 0in 0in 0in; height:53px" valign="bottom">&nbsp;</td>
			<td colspan="2" rowspan="2" style="width:40px; padding:0in 0in 0in 0in; height:53px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho</span></span></span></span></td>
			<td colspan="2" style="width:293px; padding:0in 0in 0in 0in; height:53px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632222"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632222</span></span></span></span></a></span></span></span></td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:53px" valign="bottom">&nbsp;</td>
		</tr>
		<tr>
			<td style="width:32px; padding:0in 0in 0in 0in; height:24px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="line-height:17.9pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">15.</span></span></span></span></span></td>
			<td colspan="2" style="width:293px; padding:0in 0in 0in 0in; height:24px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="line-height:17.9pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">| <i>x</i> | ≤ 3; | <i>y</i> | ≤ 5&nbsp; <i>x</i>, <i>y</i> </span><span style="font-size:15.5pt"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span><span style="font-size:15.5pt"> <i>Z</i></span></span></span></span></span></td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:24px" valign="bottom">&nbsp;</td>
		</tr>
		<tr>
			<td colspan="2" rowspan="2" style="width:39px; padding:0in 0in 0in 0in; height:26px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Biết</span></span></span></span></td>
			<td colspan="2" style="width:80px; padding:0in 0in 0in 0in; height:26px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">x </span></i><span style="font-size:15.5pt">−<i> y </i>= 2</span></span></span></span></td>
			<td rowspan="2" style="width:247px; padding:0in 0in 0in 0in; height:26px" valign="bottom"><span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">. Tìm x và y</span></span></span></span></td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:26px" valign="bottom">&nbsp;</td>
		</tr>
		<tr>
			<td style="width:33px; padding:0in 0in 0in 0in; height:69px" valign="bottom">&nbsp;</td>
			<td style="width:47px; padding:0in 0in 0in 0in; height:69px" valign="bottom">&nbsp;</td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:69px" valign="bottom">&nbsp;</td>
		</tr>
	</tbody>
</table>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-18.jpeg" width="99" /><br />
<span style="page:Section5"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632212"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632212</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="16">
	<li style="margin-right:397px"><span style="page:Section5"><span style="font-size:11pt"><span style="line-height:137%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:137%">Tính tổng các số nguyên </span></span><i><span style="font-size:15.5pt"><span style="line-height:137%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:137%">, biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:137%">− 17 ≤</span></span> <i><span style="font-size:15.5pt"><span style="line-height:137%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:137%">≤ 18</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">| &lt; 25</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-19.jpeg" width="99" /><br />
<br />
<span style="page:Section5"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632162"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632162</span></span></span></span></a></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">17. Cho </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">| = 7; |</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">| = 20</span><span style="font-size:15.5pt"> với </span><i><span style="font-size:15.5pt">x</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span> <i><span style="font-size:15.5pt">Z</span></i><span style="font-size:15.5pt">. Tính </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">y</span></i></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section6"><span style="page:Section6"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page6"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-20.jpeg" width="99" /><br />
<br />
<span style="page:Section6"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632172"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632172</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="18">
	<li><span style="page:Section6"><span style="font-size:11pt"><span style="line-height:180%"><span style="tab-stops:25.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:180%">Tìm các số nguyên x biết rằng </span></span><span style="font-size:15.5pt"><span style="line-height:180%">10 = 10 + 9 + 8 + . . . +</span></span> <i><span style="font-size:15.5pt"><span style="line-height:180%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:180%">, trong đó vế phải là tổng các số nguyên liên tiếp viết theo thứ tự giảm dần.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-21.jpeg" width="99" /><br />
<span style="page:Section6"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632192"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632192</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="19">
	<li style="margin-right:7px"><span style="page:Section6"><span style="font-size:11pt"><span style="line-height:180%"><span style="tab-stops:25.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:180%">Tính giá trị của biểu thức </span></span><i><span style="font-size:15.5pt"><span style="line-height:180%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:180%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:180%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:180%"> biết rằng a là số nguyên âm lớn nhất có hai chữ số, b là số nguyên âm nhỏ nhất có hai chữ số</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-22.jpeg" width="99" /><br />
<span style="page:Section6"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632152"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632152</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="20">
	<li><span style="page:Section6"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm số nguyên a biết rằng: </span><i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">+ |<i>a</i>| = 2</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-23.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section6"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632132"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632132</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="21">
	<li style="margin-right:8px"><span style="page:Section6"><span style="font-size:11pt"><span style="line-height:150%"><span style="tab-stops:25.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:150%">Chiếc diều của bạn Minh bay cao 20m (so với mặt đất), sau một lúc độ cao của chiếc diều tăng 3m, rồi sau đó lại giảm 4m. Hỏi chiếc diều ở độ cao bao nhiêu (so với mặt đất) sau hai lần thay đổi?</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-24.jpeg" width="99" /><br />
<span style="page:Section6"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/632122"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/632122</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="22">
	<li><span style="page:Section6"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh các đẳng thức sau:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section6"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(<i>a</i> − <i>b</i>) + (<i>c</i> − <i>d</i>) − (<i>a</i> + <i>c</i>) =&nbsp; − (<i>b</i> + <i>d</i>)</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section6"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(<i>a</i> − <i>b</i>) − (<i>c</i> − <i>d</i>) + (<i>b</i> + <i>c</i>) = <i>a</i> + <i>d</i></span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-25.jpeg" width="99" /><br />
<br />
<span style="page:Section6"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/63272"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/63272</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="23">
	<li style="margin-right:199px"><span style="page:Section6"><span style="font-size:11pt"><span style="line-height:284%"><span style="tab-stops:25.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:284%">Cho </span></span><i><span style="font-size:15.5pt"><span style="line-height:284%">P</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%">=</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%">−</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">b</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">c</span></span></i><span style="font-size:15.5pt"><span style="line-height:284%"> và </span></span><i><span style="font-size:15.5pt"><span style="line-height:284%">Q</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%">= −</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">b</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%">−</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">c</span></span></i><span style="font-size:15.5pt"><span style="line-height:284%">, với </span></span><i><span style="font-size:15.5pt"><span style="line-height:284%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:284%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:284%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:284%">c</span></span></i> <span style="font-size:15.5pt"><span style="line-height:284%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span></span> <span style="font-size:15.5pt"><span style="line-height:284%">Z</span></span><span style="font-size:15.5pt"><span style="line-height:284%">. Chứng tỏ rằng </span></span><i><span style="font-size:15.5pt"><span style="line-height:284%">P</span></span></i><span style="font-size:15.5pt"><span style="line-height:284%"> và </span></span><i><span style="font-size:15.5pt"><span style="line-height:284%">Q</span></span></i><span style="font-size:15.5pt"><span style="line-height:284%"> là hai số đối nhau.</span></span></span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section7"><span style="page:Section7"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page7"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-26.jpeg" width="99" /><br />
<br />
<span style="page:Section7"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/95/63262"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/95/63262</span></span></span></span></a></span></span><br />
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<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:21.0pt">NHÂN CÁC SỐ NGUYÊN</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">24. Tính giá trị lớn nhất của biểu thức </span><i><span style="font-size:15.5pt">B</span></i> <span style="font-size:15.5pt">=&nbsp; − (<i>x</i></span> <span style="font-size:15.5pt">+ 1)</span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− | 3 −</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">| + 35.</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-27.jpeg" width="99" /><br />
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<span style="page:Section7"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633103"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633103</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="25">
	<li><span style="page:Section7"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span> <span style="font-size:15.5pt">Z</span><span style="font-size:15.5pt">, biết:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section7"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">3(2 − <i>x</i>) + 5(<i>x</i> − 6) =&nbsp; − 98</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section7"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(<i>x</i> + 7)(8 − <i>x</i>) = 0</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section7"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(<i>x</i></span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> + 1)(49 − <i>x</i></span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt">) = 0</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-28.jpeg" width="99" /><br />
<br />
<span style="page:Section7"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/63352"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/63352</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="26">
	<li style="margin-right:9px"><span style="page:Section7"><span style="font-size:11pt"><span style="line-height:129%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:129%">Chứng minh rằng với </span></span><i><span style="font-size:15.5pt"><span style="line-height:129%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:129%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:129%">b</span></span></i> <span style="font-size:15.5pt"><span style="line-height:129%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span></span> <span style="font-size:15.5pt"><span style="line-height:129%">Z</span></span> <sup><span style="font-size:25.0pt"><span style="line-height:129%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∗</span></span></span></sup><span style="font-size:15.5pt"><span style="line-height:129%">(|<i>a</i>|; |<i>b</i>| ≠ 1)</span></span><span style="font-size:15.5pt"><span style="line-height:129%"> và </span></span><i><span style="font-size:15.5pt"><span style="line-height:129%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:129%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:129%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:129%"> khác dấu thì </span></span><i><span style="font-size:15.5pt"><span style="line-height:129%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:129%">.</span></span> <i><span style="font-size:15.5pt"><span style="line-height:129%">b</span></span></i> <span style="font-size:15.5pt"><span style="line-height:129%">&lt;</span></span> <i><span style="font-size:15.5pt"><span style="line-height:129%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:129%"> và </span></span><i><span style="font-size:15.5pt"><span style="line-height:129%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:129%">.<i> b </i>&lt;<i> b</i></span></span><span style="font-size:15.5pt"><span style="line-height:129%">.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-29.jpeg" width="99" /><br />
<span style="page:Section7"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/63393"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/63393</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="27">
	<li><span style="page:Section7"><span style="font-size:11pt"><span style="line-height:175%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:175%">Dùng tính chất phân phối của phép nhân và phép cộng để chứng minh rằng Số đối của tích a.b bằng (</span></span><span style="font-size:15.5pt"><span style="line-height:175%"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span></span><span style="font-size:15.5pt"><span style="line-height:175%">a).b hoặc (</span></span><span style="font-size:15.5pt"><span style="line-height:175%"><span style="font-family:&#039;Cambria&#039;,&#039;serif&#039;">‐</span></span></span><span style="font-size:15.5pt"><span style="line-height:175%">b).a</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-30.jpeg" width="99" /><br />
<span style="page:Section7"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633142"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633142</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="28">
	<li style="margin-right:12px; text-align:justify"><span style="page:Section7"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:163%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:163%">Thêm các dấu </span></span><span style="font-size:15.5pt"><span style="line-height:163%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∗</span></span></span><span style="font-size:15.5pt"><span style="line-height:163%"> trong biểu thức </span></span><span style="font-size:15.5pt"><span style="line-height:163%">1</span></span> <span style="font-size:15.5pt"><span style="line-height:163%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∗</span></span></span> <span style="font-size:15.5pt"><span style="line-height:163%">2</span></span> <span style="font-size:15.5pt"><span style="line-height:163%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∗</span></span></span> <span style="font-size:15.5pt"><span style="line-height:163%">3</span></span><span style="font-size:15.5pt"><span style="line-height:163%"> bằng dấu các phép tính cộng, trừ, nhân, và thêm các dấu ngoặc để được kết quả là: số lớn nhất, số nhỏ nhất.</span></span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-31.jpeg" width="99" /><br />
<span style="page:Section7"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633192"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633192</span></span></span></span></a></span></span><br />
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<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">29. Cho </span><i><span style="font-size:15.5pt">a</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">c</span></i><span style="font-size:15.5pt">,</span> <span style="font-size:15.5pt"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span> <i><span style="font-size:15.5pt">Z</span></i><span style="font-size:15.5pt">. Biết </span><i><span style="font-size:15.5pt">ab</span></i> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">ac</span></i> <span style="font-size:15.5pt">+</span> <i><span style="font-size:15.5pt">bc</span></i> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">c</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">=&nbsp; − 1</span></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section8"><span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page8"></a><span style="font-size:15.5pt">Chứng minh rằng hai số a và b đối nhau.</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-32.jpeg" width="99" /><br />
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<br />
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633182"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633182</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="30">
	<li style="margin-right:519px; text-align:justify"><span style="page:Section8"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:132%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:132%">Tìm x biết: a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:132%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:132%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:132%">+ 2) = 0.</span></span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:15.5pt">(<i>x</i></span> <span style="font-size:15.5pt">+ 3)(<i>x</i></span> <span style="font-size:15.5pt">− 4) = 0.</span></span></span></span><br />
&nbsp;
<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section8"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(<i>x</i> + 2015)</span><span style="font-size:33.5pt">(</span><i><span style="font-size:15.5pt">x</span></i><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 4 </span><span style="font-size:33.5pt">)</span><span style="font-size:15.5pt"> = 0.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-33.jpeg" width="99" /><br />
<br />
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633132"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633132</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="31">
	<li style="margin-right:473px; text-align:justify"><span style="page:Section8"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:126%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:126%">Tìm </span></span><i><span style="font-size:15.5pt"><span style="line-height:126%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:126%"><span style="font-family:&#039;Lucida Sans Unicode&#039;,&#039;sans-serif&#039;">∈</span></span></span> <span style="font-size:15.5pt"><span style="line-height:126%">Z</span></span><span style="font-size:15.5pt"><span style="line-height:126%">, biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:126%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:126%">− 2)(7 −</span></span> <i><span style="font-size:15.5pt"><span style="line-height:126%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:126%">) &gt; 0</span></span><span style="font-size:15.5pt"><span style="line-height:126%">.</span></span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:15.5pt">(<i>x</i></span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 13)(<i>x</i></span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 17) &lt; 0</span><span style="font-size:15.5pt">.</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-34.jpeg" width="99" /><br />
<br />
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/63372"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/63372</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="32">
	<li style="margin-right:220px"><span style="page:Section8"><span style="font-size:11pt"><span style="line-height:132%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:132%">Thực hiện các phép tính sau một cách hợp lý: a. </span></span><span style="font-size:15.5pt"><span style="line-height:132%">(− 159). (+56) + (+43). (− 159) + (− 159)</span></span><span style="font-size:15.5pt"><span style="line-height:132%">.</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:15.5pt">(− 31). (+52) + (− 26). (− 162).</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-35.jpeg" width="99" /><br />
<br />
<span style="page:Section8"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633122"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633122</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="33">
	<li style="margin-right:452px"><span style="page:Section8"><span style="font-size:11pt"><span style="line-height:136%"><span style="tab-stops:25.55pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:136%">Tìm </span></span><i><span style="font-size:15.5pt"><span style="line-height:136%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:136%">∈</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">Z</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%"> sao cho: a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:136%">xy</span></span></i> <span style="font-size:15.5pt"><span style="line-height:136%">+ 3<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">− 7<i>y</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">= 21</span></span><span style="font-size:15.5pt"><span style="line-height:136%"> b. </span></span><span style="font-size:15.5pt"><span style="line-height:136%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">− 7)(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">+ 3) &lt; 0</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-36.jpeg" width="99" /><br />
<span style="page:Section8"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633172"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633172</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="34">
	<li><span style="page:Section8"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính nhanh, hợp lý:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section8"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">( − 45). ( − 16). ( − 125). ( − 1)</span><sup><span style="font-size:25.0pt">2000</span></sup></span></span></span></span></li>
	<li><span style="page:Section8"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">32.(132 − 247) − 132.(32 − 247)</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section9"><span style="page:Section9"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page9"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-37.jpeg" width="99" /><br />
<br />
<span style="page:Section9"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633162"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633162</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="35">
	<li style="margin-right:177px"><span style="page:Section9"><span style="font-size:11pt"><span style="line-height:122%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:122%">Có bao nhiêu số nguyên n thỏa mãn điều kiện sau: a. </span></span><span style="font-size:33.5pt"><span style="line-height:122%">(</span></span><i><span style="font-size:15.5pt"><span style="line-height:122%">n</span></span></i><sup><span style="font-size:25.0pt"><span style="line-height:122%">2</span></span></sup> <span style="font-size:15.5pt"><span style="line-height:122%">− 3</span></span> <span style="font-size:33.5pt"><span style="line-height:122%">)(</span></span><i><span style="font-size:15.5pt"><span style="line-height:122%">n</span></span></i><sup><span style="font-size:25.0pt"><span style="line-height:122%">2</span></span></sup> <span style="font-size:15.5pt"><span style="line-height:122%">− 36</span></span> <span style="font-size:33.5pt"><span style="line-height:122%">)</span></span> <span style="font-size:15.5pt"><span style="line-height:122%">= 0</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section9"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:33.5pt">(</span><i><span style="font-size:15.5pt">n</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 3</span> <span style="font-size:33.5pt">)(</span><i><span style="font-size:15.5pt">n</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 36</span> <span style="font-size:33.5pt">)</span> <span style="font-size:15.5pt">&lt; 0</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-38.jpeg" width="99" /><br />
<br />
<span style="page:Section9"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/633112"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/633112</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="36">
	<li><span style="page:Section9"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính giá trị của biểu thức:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section9"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">M </span></i><span style="font-size:15.5pt">=<i> ax </i>+<i> ay </i>+<i> bx </i>+<i> by </i></span><span style="font-size:15.5pt">biết</span><i><span style="font-size:15.5pt"> a </span></i><span style="font-size:15.5pt">+<i> b </i>=&nbsp; − 3;<i> x </i>+<i> y </i>= 17</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section9"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">N </span></i><span style="font-size:15.5pt">=<i> ax </i>−<i> ay </i>+<i> bx </i>−<i> by </i></span><span style="font-size:15.5pt">biết</span><i><span style="font-size:15.5pt"> a </span></i><span style="font-size:15.5pt">+<i> b </i>=&nbsp; − 7;<i> x </i>−<i> y </i>=&nbsp; − 18</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-39.jpeg" width="99" /><br />
<br />
<span style="page:Section9"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/98/63362"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/98/63362</span></span></span></span></a></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section10"><span style="page:Section10"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page10"></a><span style="font-size:31.5pt">II. ƯỚC VÀ BỘI CỦA SỐ NGUYÊN</span></span></span></span><br />
<img alt="" height="5" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-40.jpeg" width="807" /><br />
<br />
<br />
<br />
<br />
<span style="page:Section10"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:21.0pt">TÌM ƯỚC VÀ BỘI CỦA SỐ NGUYÊN</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">n</span></i><sup><span style="font-size:25.0pt">2</span></sup><i> </i><span style="font-size:15.5pt">+ 2<i>n </i>+ 4</span></span></span><br />
<span style="font-size:11pt"><span style="line-height:77%"><span style="tab-stops:228.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:8.5pt"><span style="line-height:77%">37. Tìm mọi </span></span><i><span style="font-size:8.5pt"><span style="line-height:77%">n</span></span></i> <span style="font-size:8.5pt"><span style="line-height:77%">∈</span></span> <span style="font-size:8.5pt"><span style="line-height:77%">Z</span></span><span style="font-size:8.5pt"><span style="line-height:77%"> để</span></span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; là số nguyên.</span></span></span></span></span><br />
<img alt="" height="2" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-41.jpeg" width="218" /><br />
<span style="page:Section10"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">n </span></i><span style="font-size:15.5pt">+ 1</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-42.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section10"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/101/63472"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/101/63472</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="38">
	<li style="margin-right:453px"><span style="page:Section10"><span style="font-size:11pt"><span style="line-height:136%"><span style="tab-stops:25.55pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:136%">Tìm </span></span><i><span style="font-size:15.5pt"><span style="line-height:136%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:136%">∈</span></span> <span style="font-size:15.5pt"><span style="line-height:136%">Z</span></span><span style="font-size:15.5pt"><span style="line-height:136%">, biết: a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:136%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:136%">+ 2</span></span><span style="font-size:15.5pt"><span style="line-height:136%"> là ước của 7. b. </span></span><span style="font-size:15.5pt"><span style="line-height:136%">2<i>a</i></span></span><span style="font-size:15.5pt"><span style="line-height:136%"> là ước của ‐10. c. 12 là bội của </span></span><span style="font-size:15.5pt"><span style="line-height:136%">2<i>a</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">+ 1</span></span><span style="font-size:15.5pt"><span style="line-height:136%">.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-43.jpeg" width="99" /><br />
<span style="page:Section10"><span style="font-size:11pt"><span style="line-height:92%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:92%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/101/63431"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/101/63431</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="39">
	<li><span style="page:Section10"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm </span><i><span style="font-size:15.5pt">x</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">∈</span> <span style="font-size:15.5pt">Z</span><span style="font-size:15.5pt">, biết:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section10"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">( − 3 − <i>x</i>)(<i>y</i> + 2) =&nbsp; − 5</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section10"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">4(<i>x</i> + 7)(5 − <i>y</i>) = 28</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-44.jpeg" width="99" /><br />
<br />
<span style="page:Section10"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/101/634152"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/101/634152</span></span></span></span></a></span></span><br />
<br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:12.5pt">¯</span></span></span></span><br />
&nbsp;
<ol start="40">
	<li style="margin-right:255px"><span style="page:Section10"><span style="font-size:11pt"><span style="line-height:134%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:134%">Tìm chữ số tận cùng của số </span></span><span style="font-size:15.5pt"><span style="line-height:134%">1234<i>a</i></span></span><span style="font-size:15.5pt"><span style="line-height:134%"> sao cho a. Số đó chia hết cho 5</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section10"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:139%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:139%">b. Số đó chia hết cho 6. c. Số đó chia hết cho 8.</span></span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-45.jpeg" width="99" /><br />
<span style="page:Section10"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/101/634a21"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/101/634a21</span></span></span></span></a></span></span><br />
<br />
<br />
<span style="font-size:11pt"><span style="line-height:95%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:21.0pt"><span style="line-height:95%">BÀI TOÁN LIÊN QUAN ĐẾN TÌM ƯỚC VÀ BỘI CỦA SỐ NGUYÊN</span></span></span></span></span></span></div>
&nbsp;

<div class="Section11"><span style="page:Section11"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">41. Chứng minh rằng nếu </span><i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">∈</span> <span style="font-size:15.5pt">Z</span><span style="font-size:15.5pt"> thì:</span></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section12">
<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section12"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page11"></a><i><span style="font-size:15.5pt">P </span></i><span style="font-size:15.5pt">=<i> a</i>(<i>a </i>+ 2) −<i> a</i>(<i>a </i>− 5) − 7<i> </i></span><span style="font-size:15.5pt">là bội của 7.</span></span></span></span></span></li>
</ol>
<br />
<br />
&nbsp;
<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section12"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Q </span></i><span style="font-size:15.5pt">= (<i>a </i>− 2)(<i>a </i>+ 3) − (<i>a </i>− 3)(<i>a </i>+ 2)<i> </i></span><span style="font-size:15.5pt">là số chẵn.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-46.jpeg" width="99" /><br />
<br />
<span style="page:Section12"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/63442"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/63442</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="42">
	<li style="margin-right:496px"><span style="page:Section12"><span style="font-size:11pt"><span style="line-height:112%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:112%">Tìm </span></span><i><span style="font-size:15.5pt"><span style="line-height:112%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%">∈</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">Z</span></span><span style="font-size:15.5pt"><span style="line-height:112%">, biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:112%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">+ 3)</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">⋮</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">+ 1)</span></span><span style="font-size:15.5pt"><span style="line-height:112%">. b. </span></span><span style="font-size:15.5pt"><span style="line-height:112%">(3<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">+ 5)</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">⋮</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">− 2)</span></span><span style="font-size:15.5pt"><span style="line-height:112%">. c. </span></span><span style="font-size:15.5pt"><span style="line-height:112%">(2 − 4<i>x</i>)</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">⋮</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">− 1)</span></span><span style="font-size:15.5pt"><span style="line-height:112%">.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-47.jpeg" width="99" /><br />
<span style="page:Section12"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/63452"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/63452</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="43">
	<li style="margin-right:440px"><span style="page:Section12"><span style="font-size:11pt"><span style="line-height:127%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:127%">Tìm cặp số </span></span><i><span style="font-size:15.5pt"><span style="line-height:127%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:127%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:127%">y</span></span></i> <span style="font-size:15.5pt"><span style="line-height:127%">∈</span></span> <span style="font-size:15.5pt"><span style="line-height:127%">Z</span></span><span style="font-size:15.5pt"><span style="line-height:127%">, biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:127%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:127%">− 2)(<i>y</i></span></span> <span style="font-size:15.5pt"><span style="line-height:127%">+ 3) = 15</span></span><span style="font-size:15.5pt"><span style="line-height:127%">.</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section12"><span style="font-size:11pt"><span style="line-height:148%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:148%">b. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">(3<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:148%">+ 2)(1 −</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">y</span></span></i><span style="font-size:15.5pt"><span style="line-height:148%">) = − 7</span></span><span style="font-size:15.5pt"><span style="line-height:148%">. c. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">5<i>xy</i></span></span> <span style="font-size:15.5pt"><span style="line-height:148%">− 5<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:148%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">y</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">= 5</span></span><span style="font-size:15.5pt"><span style="line-height:148%">.</span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-48.jpeg" width="99" /><br />
<span style="page:Section12"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/63462"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/63462</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="44">
	<li style="margin-right:1px"><span style="page:Section12"><span style="font-size:11pt"><span style="line-height:184%"><span style="tab-stops:25.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:184%">Chứng minh rằng nếu hai số </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:184%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%"> là hai số nguyên khác 0 và </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%"> là bội của </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%">; </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%"> là bội của </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%"> thì </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:184%">=</span></span> <i><span style="font-size:15.5pt"><span style="line-height:184%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%"> hoặc </span></span><i><span style="font-size:15.5pt"><span style="line-height:184%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:184%">= −</span></span> <i><span style="font-size:15.5pt"><span style="line-height:184%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:184%">.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-49.jpeg" width="99" /><br />
<span style="page:Section12"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/63482"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/63482</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="45">
	<li><span style="page:Section12"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng: Nếu </span><span style="font-size:15.5pt">5<i>x</i></span> <span style="font-size:15.5pt">+ 47<i>y</i></span><span style="font-size:15.5pt"> chia hết cho 17 thì </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">+ 6<i>y</i></span><span style="font-size:15.5pt"> cũng chia hết cho</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="17">
	<li><span style="page:Section12"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">và ngược lại.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-50.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section12"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/63493"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/63493</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="46">
	<li><span style="page:Section12"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng: </span><i><span style="font-size:15.5pt">A</span></i> <span style="font-size:15.5pt">= 1 − 3 + 3</span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 3</span><sup><span style="font-size:25.0pt">3</span></sup> <span style="font-size:15.5pt">+</span> <span style="font-size:15.5pt">⋯</span> <span style="font-size:15.5pt">+ 3</span><sup><span style="font-size:25.0pt">98</span></sup> <span style="font-size:15.5pt">− 3</span><sup><span style="font-size:25.0pt">99</span></sup>&nbsp; <span style="font-size:15.5pt">⋮</span> <span style="font-size:15.5pt">4</span><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-51.jpeg" width="99" /><br />
<br />
<span style="page:Section12"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634103"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634103</span></span></span></span></a></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section13">
<ol start="47">
	<li><span style="page:Section13"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page12"></a><span style="font-size:15.5pt">Chứng minh rằng nếu a chia hết cho b thì </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">|</span><span style="font-size:15.5pt"> chia hết cho </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">b</span></i> <span style="font-size:15.5pt">|</span><span style="font-size:15.5pt"> .</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-52.jpeg" width="99" /><br />
<br />
<br />
<br />
<br />
<br />
<span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634112"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634112</span></span></span></span></a></span></span></span>

<table class="Table" style="border-collapse:collapse">
	<tbody>
		<tr>
			<td style="width:32px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">48.</span></span></span></span></td>
			<td rowspan="2" style="width:39px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho</span></span></span></span></td>
			<td colspan="5" style="width:121px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="line-height:23.25pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">a</span></i><span style="font-size:15.5pt">,<i> b</i>,<i> c</i>,<i> m </i></span><span style="font-size:15.5pt">∈</span><i> </i><span style="font-size:15.5pt">Z</span></span></span></span></span></td>
			<td rowspan="2" style="width:204px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">. Chứng minh rằng nếu</span></span></span></span></td>
			<td style="width:19px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">a</span></i></span></span></span></td>
			<td style="width:139px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="line-height:23.25pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">⋮ </span><i><span style="font-size:15.5pt">m</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt"> ⋮ </span><i><span style="font-size:15.5pt">m</span></i></span></span></span></span></td>
			<td rowspan="2" style="width:23px; padding:0in 0in 0in 0in; height:31px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">và</span></span></span></span></td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:31px" valign="bottom">&nbsp;</td>
		</tr>
		<tr>
			<td style="width:32px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
			<td style="width:12px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
			<td style="width:31px; padding:0in 0in 0in 0in; height:20px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="line-height:14.85pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:12.5pt">⋮</span></span></span></span></span></td>
			<td style="width:25px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
			<td style="width:28px; padding:0in 0in 0in 0in; height:20px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="line-height:14.85pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">thì</span></span></span></span></span></td>
			<td style="width:25px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
			<td style="width:19px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
			<td style="width:139px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:20px" valign="bottom">&nbsp;</td>
		</tr>
		<tr>
			<td colspan="3" style="width:83px; padding:0in 0in 0in 0in; height:33px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">a </span></i><span style="font-size:15.5pt">+<i> b </i>+<i> c</i></span></span></span></span></td>
			<td style="width:31px; padding:0in 0in 0in 0in; height:33px" valign="bottom">&nbsp;</td>
			<td style="width:25px; padding:0in 0in 0in 0in; height:33px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">m</span></i></span></span></span></td>
			<td style="width:28px; padding:0in 0in 0in 0in; height:33px" valign="bottom">&nbsp;</td>
			<td style="width:25px; padding:0in 0in 0in 0in; height:33px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">c</span></i></span></span></span></td>
			<td style="width:204px; padding:0in 0in 0in 0in; height:33px" valign="bottom"><span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">⋮ </span><i><span style="font-size:15.5pt">m</span></i><span style="font-size:15.5pt">.</span></span></span></span></td>
			<td style="width:19px; padding:0in 0in 0in 0in; height:33px" valign="bottom">&nbsp;</td>
			<td style="width:139px; padding:0in 0in 0in 0in; height:33px" valign="bottom">&nbsp;</td>
			<td style="width:23px; padding:0in 0in 0in 0in; height:33px" valign="bottom">&nbsp;</td>
			<td style="width:0px; padding:0in 0in 0in 0in; height:33px" valign="bottom">&nbsp;</td>
		</tr>
	</tbody>
</table>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-53.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634122"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634122</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="49">
	<li style="margin-right:13px"><span style="page:Section13"><span style="font-size:11pt"><span style="line-height:147%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:147%">Cho </span></span><i><span style="font-size:15.5pt"><span style="line-height:147%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:147%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:147%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:147%">,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:147%">m</span></span></i> <span style="font-size:15.5pt"><span style="line-height:147%">∈</span></span> <span style="font-size:15.5pt"><span style="line-height:147%">Z,</span></span> <i><span style="font-size:15.5pt"><span style="line-height:147%">m</span></span></i> <span style="font-size:15.5pt"><span style="line-height:147%">&gt; 0</span></span><span style="font-size:15.5pt"><span style="line-height:147%">. Chứng minh rằng nếu a, b chia cho m có cùng số dư thì </span></span><i><span style="font-size:15.5pt"><span style="line-height:147%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:147%">−</span></span> <i><span style="font-size:15.5pt"><span style="line-height:147%">b</span></span></i> <span style="font-size:15.5pt"><span style="line-height:147%">⋮</span></span> <i><span style="font-size:15.5pt"><span style="line-height:147%">m</span></span></i><span style="font-size:15.5pt"><span style="line-height:147%">.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-54.jpeg" width="99" /><br />
<span style="page:Section13"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634132"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634132</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="50">
	<li><span style="page:Section13"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm </span><i><span style="font-size:15.5pt">n</span></i> <span style="font-size:15.5pt">∈</span> <i><span style="font-size:15.5pt">Z</span></i><span style="font-size:15.5pt"> để </span><i><span style="font-size:15.5pt">n</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 7</span><span style="font-size:15.5pt"> là bội của </span><i><span style="font-size:15.5pt">n</span></i> <span style="font-size:15.5pt">+ 3</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-55.jpeg" width="99" /><br />
<br />
<span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634162"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634162</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="51">
	<li><span style="page:Section13"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm các giá trị nguyên dương nhỏ hơn 10 của x và y sao cho </span><span style="font-size:15.5pt">3<i>x</i></span> <span style="font-size:15.5pt">− 4<i>y</i></span> <span style="font-size:15.5pt">=&nbsp; − 21</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-56.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634172"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634172</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="52">
	<li><span style="page:Section13"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">∈</span> <i><span style="font-size:15.5pt">Z</span></i><span style="font-size:15.5pt"> sao cho: </span><i><span style="font-size:15.5pt">xy</span></i> <span style="font-size:15.5pt">+ 3<i>x</i></span> <span style="font-size:15.5pt">− 2<i>y</i></span> <span style="font-size:15.5pt">= 11</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-57.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section13"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634182"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634182</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="53">
	<li style="text-align:justify"><span style="page:Section13"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:175%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:175%">Số 36 chia hết cho số nguyên a rồi trừ đi a. Lấy kết quả này chia cho a rồi trừ đi a. Lại lấy kết quả này chia cho a rồi trừ đi a. Cuối cùng ta được số ‐a. Tìm số a.</span></span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-58.jpeg" width="99" /><br />
<span style="page:Section13"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634192"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634192</span></span></span></span></a></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section14">
<ol start="54">
	<li><span style="page:Section14"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page13"></a><span style="font-size:15.5pt">Cho </span><i><span style="font-size:15.5pt">a</span></i><span style="font-size:15.5pt">,</span> <i><span style="font-size:15.5pt">b</span></i> <span style="font-size:15.5pt">∈</span> <i><span style="font-size:15.5pt">Z</span></i><span style="font-size:15.5pt">. Chứng minh rằng:</span></span></span></span></span></li>
</ol>
<br />
<br />
<span style="page:Section14"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Nếu </span><i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">+ 4<i>b</i></span><span style="font-size:15.5pt"> chia hết cho 13 thì </span><span style="font-size:15.5pt">10<i>a</i></span> <span style="font-size:15.5pt">+</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt"> cũng chia hết cho 13.</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-59.jpeg" width="99" /><br />
<br />
<br />
<br />
<br />
<span style="page:Section14"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/102/634202"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/102/634202</span></span></span></span></a></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section15"><span style="page:Section15"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page14"></a><span style="font-size:31.5pt">III. MỘT SỐ BÀI TOÁN TỔNG HỢP</span></span></span></span><br />
<img alt="" height="5" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-60.jpeg" width="807" /><br />
<br />
<br />
<br />
<br />
<span style="page:Section15"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:21.0pt">CÁC DẠNG TOÁN THƯỜNG GẶP</span></span></span></span><br />
&nbsp;
<ol start="55">
	<li style="margin-right:244px"><span style="page:Section15"><span style="font-size:11pt"><span style="line-height:165%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:165%">Thực hiện phép tính (tính hợp lý nếu có thể) a. </span></span><span style="font-size:15.5pt"><span style="line-height:165%">− &#91; − 345 + 1234 − 2014&#93; − (345 − 1234)</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section15"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:145%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:145%">b. </span></span><span style="font-size:15.5pt"><span style="line-height:145%">654 + {374 − &#91;654 − ( + 126)&#93;}</span></span><span style="font-size:15.5pt"><span style="line-height:145%"> c. </span></span><span style="font-size:15.5pt"><span style="line-height:145%">( − 31).47 + ( − 31).52 + ( − 31)</span></span><span style="font-size:15.5pt"><span style="line-height:145%"> d. </span></span><span style="font-size:15.5pt"><span style="line-height:145%">24.(16 − 5) − 16.(24 − 5)</span></span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-61.jpeg" width="99" /><br />
<span style="page:Section15"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/63544"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/63544</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="56">
	<li style="margin-right:472px"><span style="page:Section15"><span style="font-size:11pt"><span style="line-height:132%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:132%">Tìm x thuộc Z biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:132%">|<i>x</i>| ≤ 3</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section15"><span style="font-size:11pt"><span style="line-height:138%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:138%">b. </span></span><span style="font-size:15.5pt"><span style="line-height:138%">| − 15| − |<i>x</i>| = | − 12|</span></span><span style="font-size:15.5pt"><span style="line-height:138%"> c. </span></span><span style="font-size:15.5pt"><span style="line-height:138%">− 2 &lt; |<i>x</i>| &lt; 4</span></span></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">d. |x| &gt; 4 và x &lt; ‐10</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-62.jpeg" width="99" /><br />
<br />
<span style="page:Section15"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/63554"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/63554</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="57">
	<li style="margin-right:452px"><span style="page:Section15"><span style="font-size:11pt"><span style="line-height:132%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:132%">Tìm x, y thuộc Z biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:132%">(<i>x</i>– 1)(<i>y</i></span></span> <span style="font-size:15.5pt"><span style="line-height:132%">+ 1) = 17</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section15"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><i><span style="font-size:15.5pt">xy</span></i><span style="font-size:15.5pt">– 2<i>x</i>– 2<i>y</i></span> <span style="font-size:15.5pt">= 0</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">c. </span><span style="font-size:15.5pt">|<i>x</i></span> <span style="font-size:15.5pt">− 2| + |<i>y</i></span> <span style="font-size:15.5pt">+</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">− 3| ≤ 0</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">d. </span><span style="font-size:15.5pt">(<i>x</i></span> <span style="font-size:15.5pt">+ 1)</span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">+ (<i>x</i></span> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">+ 2)</span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">= 0</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-63.jpeg" width="99" /><br />
<br />
<span style="page:Section15"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/63564"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/63564</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="58">
	<li><span style="page:Section15"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính hợp lí:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section15"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">159.(18– 59)– 59.(18 − 159)</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section15"><span style="font-size:11pt"><span style="line-height:87%"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:87%">( − 5)</span></span><sup><span style="font-size:25.0pt"><span style="line-height:87%">5</span></span></sup><span style="font-size:15.5pt"><span style="line-height:87%">. ( − 19).32. ( − 2005)</span></span><sup><span style="font-size:25.0pt"><span style="line-height:87%">0</span></span></sup></span></span></span></span></span></li>
	<li><span style="page:Section15"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">( − 25).68 + ( − 34). ( − 250)</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="4" style="list-style-type:lower-alpha">
	<li><span style="page:Section15"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">54 + 55 + 56 + 57 + 58– (64 + 65 + 66 + 67 + 68)</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section16"><img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-64.jpeg" width="99" /><span style="page:Section16"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page15"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635164"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635164</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="59">
	<li style="margin-right:479px"><span style="page:Section16"><span style="font-size:11pt"><span style="line-height:111%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:111%">Tìm x </span></span><span style="font-size:15.5pt"><span style="line-height:111%">∈</span></span><span style="font-size:15.5pt"><span style="line-height:111%"> Z biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:111%">12</span></span> <span style="font-size:15.5pt"><span style="line-height:111%">⋮</span></span> <i><span style="font-size:15.5pt"><span style="line-height:111%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:111%"> và </span></span><i><span style="font-size:15.5pt"><span style="line-height:111%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:111%">&lt; 0</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section16"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:15.5pt">( − 8)</span> <span style="font-size:15.5pt">⋮</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">; 12</span> <span style="font-size:15.5pt">⋮</span> <i><span style="font-size:15.5pt">x</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">c. </span><i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">⋮</span> <span style="font-size:15.5pt">( − 9)</span><span style="font-size:15.5pt"> và x </span><span style="font-size:15.5pt">⋮</span><span style="font-size:15.5pt"> 12và </span><span style="font-size:15.5pt">20 &lt;</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">&lt; 50</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">d. x </span><span style="font-size:15.5pt">⋮</span><span style="font-size:15.5pt"> 4 và x </span><span style="font-size:15.5pt">⋮</span><span style="font-size:15.5pt"> (‐6) và </span><span style="font-size:15.5pt">− 20 &lt;</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">&lt;&nbsp; − 10</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-65.jpeg" width="99" /><br />
<br />
<span style="page:Section16"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635214"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635214</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="60">
	<li style="margin-right:480px; text-align:justify"><span style="page:Section16"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:127%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:127%">Tìm x </span></span><span style="font-size:15.5pt"><span style="line-height:127%">∈</span></span><span style="font-size:15.5pt"><span style="line-height:127%"> Z biết a. </span></span><span style="font-size:15.5pt"><span style="line-height:127%">| 2<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:127%">+ 1 | − 3 = 4</span></span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section16"><span style="font-size:11pt"><span style="line-height:148%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:148%">b. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">|</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">+ 3 | + |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">+ 5 | = 3<i>x</i></span></span><span style="font-size:15.5pt"><span style="line-height:148%"> c. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">| 5 + |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:148%">– 2 | | = 12</span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-66.jpeg" width="99" /><br />
<span style="page:Section16"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635264"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635264</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="61">
	<li><span style="page:Section16"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm nghiệm nguyên dương của phương trình: </span><i><span style="font-size:15.5pt">x</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 2<i>y</i></span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">= 5</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-67.jpeg" width="99" /><br />
<br />
<span style="page:Section16"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635314"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635314</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="62">
	<li style="margin-right:415px"><span style="page:Section16"><span style="font-size:11pt"><span style="line-height:135%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:135%">Với x </span></span><span style="font-size:15.5pt"><span style="line-height:135%">∈</span></span><span style="font-size:15.5pt"><span style="line-height:135%"> Z hãy so sánh a. 2003x và 2005x</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section16"><span style="font-size:11pt"><span style="line-height:92%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:92%">b. </span></span><i><span style="font-size:15.5pt"><span style="line-height:92%">x</span></span></i><sup><span style="font-size:25.0pt"><span style="line-height:92%">2</span></span></sup><span style="font-size:15.5pt"><span style="line-height:92%"> và 6x</span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-68.jpeg" width="99" /><br />
<span style="page:Section16"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635274"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635274</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="63">
	<li><span style="page:Section16"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm nhanh:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section16"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">− 64.159 + 136.( − 8)</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> + 123.64</span></span></span></span></span></li>
	<li><span style="page:Section16"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">15.12– 3.10.7 − 30.99</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section16"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">28.19 + ( − 21).4– 14.10– 11.28</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="4" style="list-style-type:lower-alpha">
	<li><span style="page:Section16"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">38(25– 17)– 25(38– 17) + 13.( − 83)</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section17"><span style="page:Section17"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page16"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-69.jpeg" width="99" /><br />
<br />
<span style="page:Section17"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635224"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635224</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="64">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính giá trị biểu thức:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">A </span></i><span style="font-size:15.5pt">=<i> a </i>+ 9–<i> a</i>– 25–<i> a </i>+ 15 + 2<i>a </i></span><span style="font-size:15.5pt">biết</span><i><span style="font-size:15.5pt"> a </span></i><span style="font-size:15.5pt">= 25</span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section17"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><i><span style="font-size:15.5pt">B</span></i> <span style="font-size:15.5pt">= |</span> <i><span style="font-size:15.5pt">a</span></i><span style="font-size:15.5pt">–</span> <i><span style="font-size:15.5pt">b</span></i> <span style="font-size:15.5pt">| +</span> <i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">+ 7– 8 + ( − 9)– ( − 8)</span><span style="font-size:15.5pt"> biết </span><i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">=&nbsp; − 4;</span> <i><span style="font-size:15.5pt">b</span></i> <span style="font-size:15.5pt">= 5</span></span></span></span><br />
&nbsp;
<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">C </span></i><span style="font-size:15.5pt">= (<i>a </i>+<i> b</i>)(<i>a</i>.<i> a</i>–<i> a</i>.<i> b </i>+<i> b</i>.<i> b</i>)<i> </i></span><span style="font-size:15.5pt">biết</span><i><span style="font-size:15.5pt"> a </span></i><span style="font-size:15.5pt">= 5;<i> b </i>=&nbsp; − 7</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="4" style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">D= </span><span style="font-size:33.5pt">(</span><i><span style="font-size:15.5pt">a</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">b</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:33.5pt">)</span><span style="font-size:15.5pt">: &#91;(<i>a</i></span> <span style="font-size:15.5pt">+</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt">). (<i>a</i></span> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt">)&#93;</span><span style="font-size:15.5pt"> biết </span><i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">= 5;</span> <i><span style="font-size:15.5pt">b</span></i> <span style="font-size:15.5pt">=&nbsp; − 3</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-70.jpeg" width="99" /><br />
<span style="page:Section17"><span style="font-size:11pt"><span style="line-height:98%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:98%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635174"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635174</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="65">
	<li style="margin-right:117px"><span style="page:Section17"><span style="font-size:11pt"><span style="line-height:132%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:132%">Tính tổng S và tích P của tất cả các số nguyên x biết rằng: a. </span></span><span style="font-size:15.5pt"><span style="line-height:132%">− 9 &lt;</span></span> <i><span style="font-size:15.5pt"><span style="line-height:132%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:132%">≤ 6</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section17"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><span style="font-size:15.5pt">− 5 ≤</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">&lt; 4</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:148%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:148%">c. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">− 567 &lt;</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">&lt; 567</span></span><span style="font-size:15.5pt"><span style="line-height:148%"> d. </span></span><span style="font-size:15.5pt"><span style="line-height:148%">|<i>x</i>| ≤ 4</span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-71.jpeg" width="99" /><br />
<span style="page:Section17"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635124"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635124</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="66">
	<li style="margin-right:264px"><span style="page:Section17"><span style="font-size:11pt"><span style="line-height:132%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:132%">Tìm GTLN, GTNN (nếu có của biểu thức) a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:132%">A</span></span></i> <span style="font-size:15.5pt"><span style="line-height:132%">= |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:132%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:132%">+ 3 | + 2014</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section17"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">b. </span><i><span style="font-size:15.5pt">B</span></i> <span style="font-size:15.5pt">=&nbsp; − |</span> <i><span style="font-size:15.5pt">x</span></i> <span style="font-size:15.5pt">+ 4 | + 2015</span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:148%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:148%">c. </span></span><i><span style="font-size:15.5pt"><span style="line-height:148%">C</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">= |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">+ 3 | + |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">y</span></span></i><span style="font-size:15.5pt"><span style="line-height:148%">–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">+ 5 | − 7</span></span><span style="font-size:15.5pt"><span style="line-height:148%"> d. </span></span><i><span style="font-size:15.5pt"><span style="line-height:148%">D</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">= |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i> <span style="font-size:15.5pt"><span style="line-height:148%">+ 1 | + |</span></span> <i><span style="font-size:15.5pt"><span style="line-height:148%">x</span></span></i><span style="font-size:15.5pt"><span style="line-height:148%">– 3 |</span></span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-72.jpeg" width="99" /><br />
<span style="page:Section17"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/63574"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/63574</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="67">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính các tổng sau:</span></span></span></span></span></li>
</ol>

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="line-height:97%"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:97%">S</span></span></i><sub><span style="font-size:25.0pt"><span style="line-height:97%">1</span></span></sub><i> </i><span style="font-size:15.5pt"><span style="line-height:97%">= 1 + ( − 2) + 3 + ( − 4) + . . . + 2001 + ( − 2002) + 2003</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="line-height:79%"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:79%">S</span></span></i><sub><span style="font-size:25.0pt"><span style="line-height:79%">2</span></span></sub><i> </i><span style="font-size:15.5pt"><span style="line-height:79%">= 1 + ( − 3) + 5 + ( − 7) + . . . + 2001 + ( − 2003)</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="line-height:79%"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:79%">S</span></span></i><sub><span style="font-size:25.0pt"><span style="line-height:79%">3</span></span></sub><i> </i><span style="font-size:15.5pt"><span style="line-height:79%">= 1 − 2 − 3 + 4 + 5 − 6 − 7 + 8 +</span></span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section17"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">. . . + 2001 − 2002 − 2003 + 2004</span></span></span></span><br />
&nbsp;
<ol start="4" style="list-style-type:lower-alpha">
	<li><span style="page:Section17"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">S</span></i><sub><span style="font-size:25.0pt">4</span></sub><i> </i><span style="font-size:15.5pt">= 1 + 2 − 3 − 4 + 5 + 6 − 7 − 8 + 9 +</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section18"><span style="page:Section18"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page17"></a><span style="font-size:15.5pt">. . . + 2002 − 2003 − 2004 + 2005 + 2006</span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-73.jpeg" width="99" /><br />
<br />
<span style="page:Section18"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/63584"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/63584</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="68">
	<li><span style="page:Section18"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">So sánh P với Q biết</span></span></span></span></span></li>
</ol>

<ol start="16" style="list-style-type:upper-alpha">
	<li style="margin-right:365px"><span style="page:Section18"><span style="font-size:11pt"><span style="line-height:115%"><span style="tab-stops:14.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:115%">= <i>a</i> − {(<i>a</i> − 3) − &#91;(<i>a</i> + 3) − ( − <i>a</i> − 2)&#93;} <i>Q </i>= &#91;<i>a </i>+ (<i>a </i>+ 3)&#93; − &#91;(<i>a </i>+ 2) − (<i>a </i>− 2)&#93;</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-74.jpeg" width="99" /><br />
<br />
<br />
<br />
<span style="page:Section18"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635134"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635134</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="69">
	<li style="margin-right:307px"><span style="page:Section18"><span style="font-size:11pt"><span style="line-height:127%"><span style="tab-stops:25.5pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:127%">a, b, c, d </span></span><span style="font-size:15.5pt"><span style="line-height:127%">∈</span></span><span style="font-size:15.5pt"><span style="line-height:127%"> Z. Đơn giản các biểu thức sau: a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:127%">M</span></span></i> <span style="font-size:15.5pt"><span style="line-height:127%">= (<i>a</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:127%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:127%">) + (<i>b</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:127%">c</span></span></i><span style="font-size:15.5pt"><span style="line-height:127%">)– (<i>d</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:127%">c</span></span></i><span style="font-size:15.5pt"><span style="line-height:127%">)– (<i>a</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:127%">d</span></span></i><span style="font-size:15.5pt"><span style="line-height:127%">)</span></span></span></span></span></span></span></li>
</ol>
<span style="page:Section18"><span style="font-size:11pt"><span style="line-height:136%"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:136%">b. </span></span><i><span style="font-size:15.5pt"><span style="line-height:136%">N</span></span></i> <span style="font-size:15.5pt"><span style="line-height:136%">= (<i>a</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%">) + (<i>c</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">d</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%">)– (<i>c</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">a</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%">)– (<i>b</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">d</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%">)</span></span><span style="font-size:15.5pt"><span style="line-height:136%"> c. </span></span><i><span style="font-size:15.5pt"><span style="line-height:136%">P</span></span></i> <span style="font-size:15.5pt"><span style="line-height:136%">= (<i>a</i></span></span> <span style="font-size:15.5pt"><span style="line-height:136%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%">)(<i>a</i>–</span></span> <i><span style="font-size:15.5pt"><span style="line-height:136%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:136%">)</span></span></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">d. </span><i><span style="font-size:15.5pt">Q</span></i> <span style="font-size:15.5pt">= (<i>a</i></span> <span style="font-size:15.5pt">−</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt">)</span><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− (<i>a</i></span> <span style="font-size:15.5pt">+</span> <i><span style="font-size:15.5pt">b</span></i><span style="font-size:15.5pt">)</span><sup><span style="font-size:25.0pt">2</span></sup></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-75.jpeg" width="99" /><br />
<br />
<span style="page:Section18"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635184"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635184</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="70">
	<li><span style="page:Section18"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm x, y </span><span style="font-size:15.5pt">∈</span><span style="font-size:15.5pt"> Z biết: </span><span style="font-size:15.5pt">|</span> <i><span style="font-size:15.5pt">x</span></i><span style="font-size:15.5pt">– 8 | + |</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">+ 2 | = 2</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-76.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section18"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635234"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635234</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="71">
	<li><span style="page:Section18"><span style="font-size:11pt"><span style="line-height:109%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:109%">Một xí nghiệp mỗi ngày may được 350 bộ quần áo. Khi may theo mốt mới,với cùng khổ vải, số vải dùng để may một bộ quần áo tăng x cm và năng suất không thay đổi. Hỏi mỗi ngày số vải tăng bao nhiêu centimét biết:</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section18"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">x </span></i><span style="font-size:15.5pt">= 15</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section18"><span style="font-size:11pt"><span style="tab-stops:21.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">x </span></i><span style="font-size:15.5pt">=&nbsp; − 10</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-77.jpeg" width="99" /><br />
<br />
<span style="page:Section18"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635284"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635284</span></span></span></span></a></span></span><br />
<br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">72. Tìm các cặp số nguyên (x;y) thỏa mãn phương trình </span><span style="font-size:15.5pt">13<i>x</i></span> <span style="font-size:15.5pt">+ 5<i>y</i></span> <span style="font-size:15.5pt">= 175</span></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section19"><span style="page:Section19"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page18"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-78.jpeg" width="99" /><br />
<br />
<span style="page:Section19"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635334"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635334</span></span></span></span></a></span></span></span><br />
<br />
<br />
&nbsp;
<ol start="73">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">So sánh:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">( − 2)</span><sup><span style="font-size:25.0pt">31</span></sup><span style="font-size:15.5pt">và</span><span style="font-size:15.5pt"> ( − 3)</span><sup><span style="font-size:25.0pt">21</span></sup></span></span></span></span></li>
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">( − 81)</span><sup><span style="font-size:25.0pt">13</span></sup> <span style="font-size:15.5pt">và</span><span style="font-size:15.5pt"> ( − 243)</span><sup><span style="font-size:25.0pt">9</span></sup></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-79.jpeg" width="99" /><br />
<br />
<span style="page:Section19"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635294"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635294</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="74">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm nghiệm nguyên của phương trình </span><span style="font-size:15.5pt">3<i>xy</i></span> <span style="font-size:15.5pt">+ 6<i>x</i></span> <span style="font-size:15.5pt">+</span> <i><span style="font-size:15.5pt">y</span></i> <span style="font-size:15.5pt">− 52 = 0</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-80.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section19"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635344"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635344</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="75">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">− 2448: &#91;119 − (23 − 2.3)&#93; − ( − 4)</span><sup><span style="font-size:25.0pt">2</span></sup></span></span></span></span></li>
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">12: {390: &#91;500 − (125 + 35.7)&#93;}</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">− | − 5| + ( − 19) + 18 + |11 − 4| − 57</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="4" style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="line-height:75%"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:75%">34950: 233 − (51.78 + 51.22): 17 − </span></span><span style="font-size:33.0pt"><span style="line-height:75%">(</span></span><span style="font-size:15.5pt"><span style="line-height:75%">5</span></span><sup><span style="font-size:24.5pt"><span style="line-height:75%">6</span></span></sup><span style="font-size:15.5pt"><span style="line-height:75%"> : 5</span></span><sup><span style="font-size:24.5pt"><span style="line-height:75%">4</span></span></sup> <span style="font-size:33.0pt"><span style="line-height:75%">)</span></span><span style="font-size:15.5pt"><span style="line-height:75%">.8</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-81.jpeg" width="99" /><br />
<br />
<span style="page:Section19"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635244"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635244</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="76">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho x, y </span><span style="font-size:15.5pt">∈</span><span style="font-size:15.5pt"> Z. Chứng minh rằng:</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Nếu </span><span style="font-size:15.5pt">20<i>x</i></span> <span style="font-size:15.5pt">+ 11<i>y</i></span><span style="font-size:15.5pt"> chia hết cho 2008 thì </span><span style="font-size:15.5pt">1988<i>x</i></span> <span style="font-size:15.5pt">+ 1997<i>y</i></span><span style="font-size:15.5pt"> chia hết cho 2008</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Nếu </span><span style="font-size:15.5pt">19<i>x</i>– 5<i>y</i></span><span style="font-size:15.5pt"> chia hết cho 2010 thì </span><span style="font-size:15.5pt">1510<i>y</i>– 110<i>x</i></span><span style="font-size:15.5pt"> chia hết cho 2010</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-82.jpeg" width="99" /><br />
<br />
<span style="page:Section19"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635194"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635194</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="77">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="line-height:119%"><span style="tab-stops:25.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:119%">Cho biết </span></span><i><span style="font-size:15.5pt"><span style="line-height:119%">a</span></span></i> <span style="font-size:15.5pt"><span style="line-height:119%">+</span></span> <i><span style="font-size:15.5pt"><span style="line-height:119%">b</span></span></i><span style="font-size:15.5pt"><span style="line-height:119%"> chia hết cho 7. Chứng tỏ rằng các biểu thức sau đây cũng chia hết cho 7.</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">a </span></i><span style="font-size:15.5pt">+ 8<i>b</i></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">3<i>a</i>– 11<i>b</i></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section19"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">5<i>a</i>– 9<i>b</i> + 2009</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section20"><span style="page:Section20"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page19"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-83.jpeg" width="99" /><br />
<br />
<span style="page:Section20"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635144"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635144</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="78">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính </span><span style="font-size:15.5pt">3<i>S</i></span> <span style="font-size:15.5pt">− 2</span><sup><span style="font-size:25.0pt">2003</span></sup><span style="font-size:15.5pt"> biết rằng:</span></span></span></span></span></li>
</ol>

<ol start="19" style="list-style-type:upper-alpha">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:12.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">= 1 − 2 + 2</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 2</span><sup><span style="font-size:25.0pt">3</span></sup><span style="font-size:15.5pt"> + . . . + 2</span><sup><span style="font-size:25.0pt">2002</span></sup></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-84.jpeg" width="99" /><br />
<br />
<span style="page:Section20"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/63594"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/63594</span></span></span></span></a></span></span></span><br />
&nbsp;
<ol start="79">
	<li style="margin-right:473px"><span style="page:Section20"><span style="font-size:11pt"><span style="line-height:112%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:112%">Tìm n </span></span><span style="font-size:15.5pt"><span style="line-height:112%">∈</span></span><span style="font-size:15.5pt"><span style="line-height:112%"> Z biết: a. </span></span><i><span style="font-size:15.5pt"><span style="line-height:112%">n</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%">+ 3</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">⋮</span></span> <i><span style="font-size:15.5pt"><span style="line-height:112%">n</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%">− 1</span></span><span style="font-size:15.5pt"><span style="line-height:112%"> b. </span></span><span style="font-size:15.5pt"><span style="line-height:112%">3<i>n</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">− 1</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">⋮</span></span> <i><span style="font-size:15.5pt"><span style="line-height:112%">n</span></span></i> <span style="font-size:15.5pt"><span style="line-height:112%">+ 2</span></span><span style="font-size:15.5pt"><span style="line-height:112%"> c. </span></span><span style="font-size:15.5pt"><span style="line-height:112%">5<i>n</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">+ 3</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">⋮</span></span> <span style="font-size:15.5pt"><span style="line-height:112%">2<i>n</i></span></span> <span style="font-size:15.5pt"><span style="line-height:112%">+ 1</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-85.jpeg" width="99" /><br />
<span style="page:Section20"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635104"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635104</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="80">
	<li style="margin-right:455px"><span style="page:Section20"><span style="font-size:11pt"><span style="line-height:135%"><span style="tab-stops:25.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:135%">Tìm x thuộc Z biết: a. </span></span><span style="font-size:15.5pt"><span style="line-height:135%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:135%">+ 3)(<i>x</i>– 2) &lt; 0</span></span><span style="font-size:15.5pt"><span style="line-height:135%"> b. </span></span><span style="font-size:15.5pt"><span style="line-height:135%">(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:135%">+ 1)(<i>x</i></span></span> <span style="font-size:15.5pt"><span style="line-height:135%">+ 2) &gt; 0</span></span></span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:22.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:34.0pt">(</span><i><span style="font-size:15.5pt">x</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 1</span><span style="font-size:34.0pt"> )(</span><i><span style="font-size:15.5pt">x</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">− 9</span><span style="font-size:34.0pt"> ) </span><span style="font-size:15.5pt">&lt; 0</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-86.jpeg" width="99" /><br />
<br />
<span style="page:Section20"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635154"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635154</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="81">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng:</span></span></span></span></span></li>
</ol>

<ol style="list-style-type:upper-alpha">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:14.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">= 1 − 2 + 2</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 2</span><sup><span style="font-size:25.0pt">3</span></sup><span style="font-size:15.5pt"> + . . . − 2</span><sup><span style="font-size:25.0pt">2007</span></sup><span style="font-size:15.5pt"> + 2</span><sup><span style="font-size:25.0pt">2008</span></sup> <span style="font-size:15.5pt">⋮</span><span style="font-size:15.5pt"> 5</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-87.jpeg" width="99" /><br />
<br />
<span style="page:Section20"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635254"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635254</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="82">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:25.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.0pt">Cho </span><i><span style="font-size:15.0pt">A</span></i> <span style="font-size:15.0pt">=</span> <span style="font-size:32.0pt">(</span><span style="font-size:15.0pt">15<i>n</i></span><sup><span style="font-size:24.0pt">2</span></sup> <span style="font-size:15.0pt">− 8<i>n</i></span><sup><span style="font-size:24.0pt">2</span></sup> <span style="font-size:15.0pt">− 9<i>n</i></span><sup><span style="font-size:24.0pt">2</span></sup> <span style="font-size:32.0pt">)</span><span style="font-size:15.0pt">.</span> <span style="font-size:32.0pt">(</span> <span style="font-size:15.0pt">−</span> <i><span style="font-size:15.0pt">n</span></i><sup><span style="font-size:24.0pt">3</span></sup> <span style="font-size:15.0pt">+ 4<i>n</i></span><sup><span style="font-size:24.0pt">3</span></sup> <span style="font-size:32.0pt">)</span><span style="font-size:15.0pt">. Với giá trị nào của n thì</span></span></span></span></span></li>
</ol>
&nbsp;

<ol style="list-style-type:lower-alpha">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">A </span></i><span style="font-size:15.5pt">&gt; 0</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="2" style="list-style-type:lower-alpha">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">A </span></i><span style="font-size:15.5pt">&lt; 0</span></span></span></span></span></li>
</ol>
&nbsp;

<ol start="3" style="list-style-type:lower-alpha">
	<li><span style="page:Section20"><span style="font-size:11pt"><span style="tab-stops:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">A </span></i><span style="font-size:15.5pt">= 0</span></span></span></span></span></li>
</ol>
</div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section21"><span style="page:Section21"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page20"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-88.jpeg" width="99" /><br />
<br />
<span style="page:Section21"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/103/635304"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/103/635304</span></span></span></span></a></span></span></span><br />
<br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:21.0pt">MỘT SỐ BÀI TOÁN NÂNG CAO VÀ PHÁT TRIỂN</span></span></span></span>

<ol start="83">
	<li><span style="page:Section21"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm bộ 3 số nguyên dương</span><span style="font-size:15.5pt"> (<i>x</i>; <i>y</i>; <i>z</i>) </span><span style="font-size:15.5pt">thoả mãn:</span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section21"><span style="font-size:11pt"><span style="tab-stops:122.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">x</span></i><sup><span style="font-size:25.0pt">2</span></sup><i> </i><span style="font-size:15.5pt">+<i> y </i>−<i> z </i>= 100;<i>&nbsp;&nbsp;&nbsp; x </i>+<i> y</i></span><sup><span style="font-size:25.0pt">2</span></sup><i> </i><span style="font-size:15.5pt">−<i> z </i>= 124.</span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-89.jpeg" width="99" /><br />
<br />
<span style="page:Section21"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63615"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63615</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="84">
	<li style="margin-right:25px"><span style="page:Section21"><span style="font-size:11pt"><span style="line-height:34.45pt"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">So A2 … 2B có2012 chữso (ta&nbsp; t cảcác chữso giữa&nbsp; A vàB là2). So này&nbsp; chia he t cho 72. Hãy tı̀m các chữso A&nbsp; vàB.</span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-90.jpeg" width="99" /><br />
<br />
<span style="page:Section21"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63635"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63635</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="85">
	<li><span style="page:Section21"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tính giá trị của biểu thức</span></span></span></span></span></span></li>
</ol>

<ol style="list-style-type:upper-alpha">
	<li><span style="page:Section21"><span style="font-size:11pt"><span style="tab-stops:15.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">= 1</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 2</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> + 3</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 4</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> + 5</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 6</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> + … + 2015</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt"> − 2016</span><sup><span style="font-size:25.0pt">2</span></sup><span style="font-size:15.5pt">.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-91.jpeg" width="99" /><br />
<br />
<span style="page:Section21"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63645"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63645</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="86">
	<li><span style="page:Section21"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Dãy so dưới&nbsp; đây chı̉được tạo thành bởi các chữso 1,&nbsp; 2 và3:</span></span></span></span></span></span></li>
</ol>
<span style="page:Section21"><span style="font-size:11pt"><span style="line-height:18.25pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:14.0pt">1, 2, 2, 3, 3, 3, 1, 1, 1, 1, 2,2, 2, 2, 2, 3, 3, 3, 3 , 3, 3, 1, 1, 1, 1, 1, 1, 1,… Hỏi so thứ </span></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">100 làso nào? </span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-92.jpeg" width="99" /><br />
<br />
<br />
<br />
<span style="page:Section21"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63655"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63655</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="87">
	<li><span style="page:Section21"><span style="font-size:11pt"><span style="line-height:18.3pt"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cóbao nhiêu tam giác không ba</span><span style="font-size:15.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">젟</span></span><span style="font-size:15.5pt">ng</span><span style="font-size:15.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">숟</span></span><span style="font-size:15.5pt"> nhau cóchu vi 11 vàcóđộdài các cạnh la so nguyên? </span></span></span></span></span></span></li>
</ol>
<span style="page:Section21"><span style="font-size:11pt"><span style="line-height:34.45pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">(Chú ý: Trong một tam giác, tổng hai cạnh bất kỳ bao giờ cũng lớn hơn cạnh còn lại)</span></span></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section22"><span style="page:Section22"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page21"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-93.jpeg" width="99" /><br />
<br />
<span style="page:Section22"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/636105"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/636105</span></span></span></span></a></span></span></span></span><br />
<br />
<br />
&nbsp;
<ol start="88">
	<li style="margin-right:13px"><span style="page:Section22"><span style="font-size:11pt"><span style="line-height:31.85pt"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.0pt">Xét ta t cảcác so na </span><span style="font-size:15.0pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">젟</span></span><span style="font-size:15.0pt">m</span><span style="font-size:15.0pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">숟</span></span><span style="font-size:15.0pt"> giữa 100 và2006 được tạo thành từcác chữso 0,&nbsp; 1, 2, 3, 4 không lặp. Trong các so đó cóbao nhiêu so chia&nbsp; he t cho 6?</span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-94.jpeg" width="99" /><br />
<span style="page:Section22"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63695"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63695</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="89">
	<li><span style="page:Section22"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Ba đèn pháo hiệu được cài đặt sẽbật sáng sau một khoảng thời gian xác</span></span></span></span></span></span></li>
</ol>
<span style="page:Section22"><span style="font-size:11pt"><span style="text-justify:inter-ideograph"><span style="line-height:18.25pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:13.5pt">định. Đèn thứnha t sẽbật sáng sau mo</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">谟</span></span><span style="font-size:13.5pt">i</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">萟</span></span><span style="font-size:13.5pt">12 giây, đèn thứhai bật sáng sau mo</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">谟</span></span><span style="font-size:13.5pt">i</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">萟</span></span><span style="font-size:13.5pt">30 giây vàđèn thứba bật sáng sau mo</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">谟</span></span><span style="font-size:13.5pt">i</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">萟</span></span><span style="font-size:13.5pt">66 giây. Các đèn bật sáng đo</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">刟</span></span><span style="font-size:13.5pt">ng&nbsp; thời vào lúc 8:30 a.m. Hỏi thời gian tie p theo màcác đèn sẽbật sáng đo</span><span style="font-size:13.5pt"><span style="font-family:&#039;Arial Unicode MS&#039;,&#039;sans-serif&#039;">刟</span></span><span style="font-size:13.5pt">ng&nbsp; thời làlúc nào?</span></span></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Đáp án ghi ởdạng AhBp (tức làA giờB phút)</span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-95.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section22"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63685"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63685</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="90">
	<li><span style="page:Section22"><span style="font-size:11pt"><span style="line-height:20.8pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Ne u so </span><span style="font-size:15.5pt">20122012...2012 2011 </span><span style="font-size:15.5pt">(với n so 2012) chia he t cho</span> <span style="font-size:15.5pt">11 thı̀giátrịnhỏ</span></span></span></span></span></span></li>
</ol>
<br />
<span style="page:Section22"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:12.5pt">n</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">nha t của n làbao nhiêu?</span></span></span></span></span><br />
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-96.jpeg" width="99" /><br />
<br />
<br />
<span style="page:Section22"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63675"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63675</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="91">
	<li style="margin-right:16px"><span style="page:Section22"><span style="font-size:11pt"><span style="line-height:27.3pt"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Ne u BOOK + BOOK + BOOK + BOOK + BOOK + BOOK = TEST thı̀giátrịcủa TEST làbao nhiêu? (BOOK vàTEST làcác so có 4 chữso , các chữcái khác nhau đại diện cho các chữso khác&nbsp; nhau)</span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-97.jpeg" width="99" /><br />
<span style="page:Section22"><span style="font-size:11pt"><span style="line-height:91%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:91%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/63665"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/63665</span></span></span></span></a></span></span></span></span><br />
&nbsp;
<ol start="92">
	<li><span style="page:Section22"><span style="font-size:11pt"><span style="line-height:28.75pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho số</span><i><span style="font-size:15.5pt"> A </span></i><span style="font-size:15.5pt">= 1944</span><sup><span style="font-size:25.0pt">2005</span></sup><span style="font-size:15.5pt">. Tìm chữ số tận cùng của A.</span></span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-98.jpeg" width="99" /><br />
<br />
<span style="page:Section22"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="line-height:20.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a42"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a42</span></span></span></span></a></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="line-height:29.35pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">93. </span><span style="font-size:15.5pt">Chứng minh rằng: Nếu</span> <i><span style="font-size:15.5pt">a</span></i> <span style="font-size:15.5pt">≡ 1( mod 2)</span> <span style="font-size:15.5pt">thì</span> <i><span style="font-size:15.5pt">a</span></i><sup><span style="font-size:25.0pt">2</span></sup> <span style="font-size:15.5pt">≡ 1( mod 8)</span></span></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<div class="Section23"><img alt="" height="111" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-99.jpeg" width="111" /><span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page22"></a><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a102"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a102</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="94">
	<li><span style="page:Section23"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng:</span></span></span></span></span></li>
</ol>
<span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">1924</span><sup><span style="font-size:25.0pt">2003</span></sup><sup><span style="font-size:20.0pt">2004</span></sup><i><sup><span style="font-size:15.5pt">n</span></sup></i><span style="font-size:15.5pt"> + 1920 </span><span style="font-size:15.5pt">⋮</span><span style="font-size:15.5pt"> 124; (</span><span style="font-size:15.5pt">∀</span><i><span style="font-size:15.5pt">n</span></i> <span style="font-size:15.5pt">∈</span><span style="font-size:15.5pt"> <i>N</i> </span><span style="font-size:15.5pt">∗</span><span style="font-size:15.5pt"> )</span></span></span></span><br />
<img alt="" height="111" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-100.jpeg" width="111" /><br />
<br />
<br />
<span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a153"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a153</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="95">
	<li><span style="page:Section23"><span style="font-size:11pt"><span style="line-height:152%"><span style="tab-stops:25.65pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt"><span style="line-height:152%">Cho n là một số nguyên dương. Chứng minh rằng:Nếu A có tận cùng là 5 thì </span></span><i><span style="font-size:15.5pt"><span style="line-height:152%">A</span></span></i><i><sup><span style="font-size:25.0pt"><span style="line-height:152%">n</span></span></sup></i><i> </i><span style="font-size:15.5pt"><span style="line-height:152%">cũng có tận cùng là 5.</span></span></span></span></span></span></span></li>
</ol>
<img alt="" height="111" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-101.jpeg" width="111" /><br />
<span style="page:Section23"><span style="font-size:11pt"><span style="line-height:90%"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt"><span style="line-height:90%">Xem lời giải tại:</span></span></i></span></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a143"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a143</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="96">
	<li><span style="page:Section23"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Cho số </span><i><span style="font-size:15.5pt">A</span></i> <span style="font-size:15.5pt">= 2012</span><sup><span style="font-size:25.0pt">2013</span></sup><span style="font-size:15.5pt">. Tìm chữ số tận cùng của A.</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-102.jpeg" width="99" /><br />
<br />
<span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a92"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a92</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="97">
	<li><span style="page:Section23"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm số dư khi chia </span><span style="font-size:15.5pt">3</span><sup><span style="font-size:25.0pt">2000</span></sup><span style="font-size:15.5pt"> cho 7</span></span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-103.jpeg" width="99" /><br />
<br />
<span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a82"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a82</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="98">
	<li><span style="page:Section23"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng: </span><span style="font-size:15.5pt">9</span><i><sup><span style="font-size:25.0pt">n</span></sup></i> <span style="font-size:15.5pt">+ 1</span><span style="font-size:15.5pt"> không chia hết cho 100 với mọi số tự nhiên n.</span></span></span></span></span></li>
</ol>
<img alt="" height="111" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-104.jpeg" width="111" /><br />
<br />
<br />
<span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a132"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a132</span></span></span></span></a></span></span></span><br />
<br />
&nbsp;
<ol start="99">
	<li><span style="page:Section23"><span style="font-size:11pt"><span style="tab-stops:26.0pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Tìm số dư của số </span><i><span style="font-size:15.5pt">A</span></i> <span style="font-size:15.5pt">= 776</span><sup><span style="font-size:25.0pt">776</span></sup> <span style="font-size:15.5pt">+ 777</span><sup><span style="font-size:25.0pt">777</span></sup> <span style="font-size:15.5pt">+ 778</span><sup><span style="font-size:25.0pt">778</span></sup><span style="font-size:15.5pt"> khi chia cho 5.</span></span></span></span></span></li>
</ol>
<img alt="" height="111" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-105.jpeg" width="111" /><br />
<br />
<br />
<span style="page:Section23"><span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a122"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a122</span></span></span></span></a></span></span></span></div>

<div style="page-break-after:always"><span style="display: none;">&nbsp;</span></div>

<ol start="100">
	<li style="margin-left:6px"><span style="font-size:11pt"><span style="tab-stops:34.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a name="page23"></a><span style="font-size:15.5pt">Chứng minh rằng: </span><span style="font-size:42.5pt">(</span><span style="font-size:15.5pt">2</span><sup><span style="font-size:25.0pt">2</span></sup><sup><span style="font-size:20.0pt">2<i>n</i></span></sup> <span style="font-size:15.5pt">+ 5</span> <span style="font-size:42.5pt">)</span> <span style="font-size:15.5pt">⋮</span> <span style="font-size:15.5pt">7; (</span><span style="font-size:15.5pt">∀</span><i><span style="font-size:15.5pt">n</span></i> <span style="font-size:15.5pt">∈</span> <i><span style="font-size:15.5pt">N</span></i><span style="font-size:15.5pt">)</span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161118-106.jpeg" width="99" /><br />
<br />
<br />
<br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a72"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a72</span></span></span></span></a></span></span><br />
<br />
&nbsp;
<ol start="101">
	<li style="margin-left:6px"><span style="font-size:11pt"><span style="tab-stops:34.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.5pt">Chứng minh rằng: </span><i><span style="font-size:15.5pt">A</span></i> <span style="font-size:15.5pt">= 7.5</span><sup><span style="font-size:25.0pt">2<i>n</i></span></sup> <span style="font-size:15.5pt">+ 12.6</span><i><sup><span style="font-size:25.0pt">n</span></sup></i> <span style="font-size:15.5pt">⋮</span> <span style="font-size:15.5pt">19</span></span></span></span></li>
</ol>
<img alt="" height="99" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161119-107.jpeg" width="99" /><br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a62"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a62</span></span></span></span></a></span></span><br />
<br />
&nbsp;
<ol start="102">
	<li style="margin-left:6px"><span style="font-size:11pt"><span style="tab-stops:34.8pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><span style="font-size:15.0pt">Tìm số dư của số </span><i><span style="font-size:15.0pt">A</span></i> <span style="font-size:15.0pt">= 776</span><sup><span style="font-size:24.0pt">776</span></sup> <span style="font-size:15.0pt">+ 777</span><sup><span style="font-size:24.0pt">777</span></sup> <span style="font-size:15.0pt">+ 778</span><sup><span style="font-size:24.0pt">778</span></sup><span style="font-size:15.0pt"> khi chia cho 3.</span></span></span></span></li>
</ol>
<img alt="" height="111" src="https://thcsthanhthuy.xatamhung.edu.vn/uploads/thcsthanhthuy/news/2021_07/image-20210731161119-108.jpeg" width="111" /><br />
<br />
<br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><i><span style="font-size:15.5pt">Xem lời giải tại:</span></i></span></span><br />
<span style="font-size:11pt"><span style="font-family:&#039;Times New Roman&#039;,serif"><a href="http://tilado.edu.vn/105/634a112"><span style="font-size:15.5pt"><span style="color:rgb(0, 0, 238);"><span style="text-decoration:none"><span style="text-underline:none">http://tilado.edu.vn/105/634a112</span></span></span></span></a></span></span><br />
&nbsp;
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				Giáo viên: Lê Thi Mỹ Hạnh
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