Bài 4: Thứ tự thực hiện các phép tính. Quy tắc chuyển vế
Hướng dẫn giải Bài 1.26 (Trang 22 SGK Toán 7, Bộ Kết nối tri thức, Tập 1)
<p><strong>Hướng dẫn giải B&agrave;i 1.26 (Trang 22 SGK To&aacute;n lớp 7 - Bộ Kết nối tri thức với cuộc sống):</strong></p> <p>T&igrave;m x, biết:</p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>25</mn><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>;</mo></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfenced><mrow><mo>-</mo><mfrac><mn>5</mn><mn>7</mn></mfrac></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>9</mn><mn>14</mn></mfrac><mo>.</mo></math></p> <p><span style="text-decoration: underline;"><em><strong>Hướng dẫn giải:</strong></em></span></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><mi>x</mi><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>25</mn><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>4</mn></mfrac><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>4</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>2</mn><mn>4</mn></mfrac><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>4</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>4</mn></mfrac></math></strong></em></span></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>-</mo><mo>&#160;</mo><mfenced><mrow><mo>-</mo><mfrac><mn>5</mn><mn>7</mn></mfrac></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>9</mn><mn>14</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>9</mn><mn>14</mn></mfrac><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mfrac><mrow><mo>-</mo><mn>5</mn></mrow><mn>7</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mn>9</mn><mn>14</mn></mfrac><mo>&#160;</mo><mo>+</mo><mo>&#160;</mo><mfrac><mrow><mo>-</mo><mn>10</mn></mrow><mn>14</mn></mfrac><mspace linebreak="newline"/><mi>x</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfrac><mrow><mo>-</mo><mn>1</mn></mrow><mn>14</mn></mfrac></math></p>
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