Bài 3: Giá trị tuyệt đối của một số thực
<div data-v-a7c68f28=""><span data-v-a7c68f28="">Hướng dẫn giải Bài 2 (Trang 47, SGK Toán 7, Bộ Cánh Diều, Tập 1)</span></div>
<p><strong>B&agrave;i 2 (Trang 47, SGK To&aacute;n 7, Bộ C&aacute;nh Diều, Tập 1)</strong></p> <p>Chọn dấu "&lt;" ; "&gt;"; "=" th&iacute;ch hợp cho ?</p> <p><span style="text-decoration: underline;"><em><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mn>2</mn><mo>,</mo><mn>3</mn></mrow></mfenced><mo>&#160;</mo><mo>?</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mfrac><mn>13</mn><mn>6</mn></mfrac></mrow></mfenced><mo>;</mo></math></strong></em></span></p> <p><span style="text-decoration: underline;"><em><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mn>9</mn><mo>&#160;</mo><mo>?</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>14</mn></mrow></mfenced><mo>;</mo></math></strong></em></span></p> <p><span style="text-decoration: underline;"><em><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>c</mi><mo>)</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>7</mn><mo>,</mo><mn>5</mn></mrow></mfenced><mo>&#160;</mo><mo>?</mo><mo>&#160;</mo><mo>-</mo><mn>7</mn><mo>,</mo><mn>5</mn><mo>.</mo></math></strong></em></span></p> <p>&nbsp;</p> <p><span style="text-decoration: underline;"><em><strong>Hướng dẫn giải:</strong></em></span></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mn>2</mn><mo>,</mo><mn>3</mn></mrow></mfenced><mo>&#160;</mo><mo mathcolor="#FF0000">&#62;</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mfrac><mn>13</mn><mn>6</mn></mfrac></mrow></mfenced><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>b</mi><mo>)</mo><mo>&#160;</mo><mn>9</mn><mo>&#160;</mo><mo mathcolor="#FF0000">&#60;</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>14</mn></mrow></mfenced><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>c</mi><mo>)</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>7</mn><mo>,</mo><mn>5</mn></mrow></mfenced><mo>&#160;</mo><mo mathcolor="#FF0000">&#62;</mo><mo>&#160;</mo><mo>-</mo><mn>7</mn><mo>,</mo><mn>5</mn></math></p> <p><span style="text-decoration: underline;"><strong>Ch&uacute; &yacute;:</strong></span></p> <p>|x|&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#8805;</mo></math>x với mọi x.</p>
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