Bài 3: Giá trị tuyệt đối của một số thực
<div data-v-a7c68f28=""><span data-v-a7c68f28="">Hướng dẫn giải Bài 3 (Trang 47, SGK Toán 7, Bộ Cánh Diều, Tập 1)</span></div>
<p><strong>B&agrave;i 3 (Trang 47, SGK To&aacute;n 7, Bộ C&aacute;nh Diều, Tập 1):</strong></p> <p>T&iacute;nh gi&aacute; trị biểu thức:</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><mo>-</mo><mn>137</mn></mrow></mfenced><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>363</mn></mrow></mfenced><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>b</mi><mo>)</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>28</mn></mrow></mfenced><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfenced open="|" close="|"><mn>98</mn></mfenced><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>c</mi><mo>)</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mn>200</mn><mo>)</mo><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>25</mn></mrow></mfenced><mo>.</mo><mfenced open="|" close="|"><mn>3</mn></mfenced><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><mo>-</mo><mn>137</mn></mrow></mfenced><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>363</mn></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>137</mn><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mn>363</mn><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>500</mn><mo>.</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>b</mi><mo>)</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>28</mn></mrow></mfenced><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfenced open="|" close="|"><mn>98</mn></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>28</mn><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mn>98</mn><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mo>(</mo><mn>98</mn><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mn>28</mn><mo>)</mo><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mn>70</mn><mo>.</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>c</mi><mo>)</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mn>200</mn><mo>)</mo><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfenced open="|" close="|"><mrow><mo>-</mo><mn>25</mn></mrow></mfenced><mo>.</mo><mfenced open="|" close="|"><mn>3</mn></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mn>200</mn><mo>)</mo><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mn>25</mn><mo>.</mo><mn>3</mn><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mn>200</mn><mo>)</mo><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mn>75</mn><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mo>(</mo><mn>200</mn><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mn>75</mn><mo>)</mo><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mn>275</mn><mo>.</mo></math></p>
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