Bài 4: Liên hệ giữa phép chia và phép khai phương
Hướng dẫn giải Bài 28 (Trang 18 SGK Toán 9, Tập 1)
<p><strong>B&agrave;i 28 (Trang 18 SGK To&aacute;n 9, Tập 1):</strong></p> <p>T&iacute;nh:</p> <p>a)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mfrac><mn>289</mn><mn>225</mn></mfrac></msqrt></math>;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; b)<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>2</mn><mfrac><mn>14</mn><mn>25</mn></mfrac></msqrt></math>;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;c)<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mfrac><mrow><mn>0</mn><mo>,</mo><mn>25</mn></mrow><mn>9</mn></mfrac></msqrt></math>;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;d)<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mfrac><mrow><mn>8</mn><mo>,</mo><mn>1</mn></mrow><mrow><mn>1</mn><mo>,</mo><mn>6</mn></mrow></mfrac></msqrt></math>;</p> <p>&nbsp;</p> <p><strong><span style="text-decoration: underline;"><em>Hướng dẫn giải:</em></span></strong></p> <p>a)<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mfrac><mn>289</mn><mn>225</mn></mfrac></msqrt><mo>=</mo><mo>&#160;</mo><mfrac><msqrt><mn>289</mn></msqrt><msqrt><mn>225</mn></msqrt></mfrac><mo>=</mo><mfrac><msqrt><msup><mn>17</mn><mn>2</mn></msup></msqrt><msqrt><msup><mn>15</mn><mn>2</mn></msup></msqrt></mfrac><mo>=</mo><mo>&#160;</mo><mfrac><mn>17</mn><mn>15</mn></mfrac><mo>=</mo><mn>1</mn><mfrac><mn>2</mn><mn>15</mn></mfrac></math></p> <p>b)<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>2</mn><mfrac><mn>14</mn><mn>25</mn></mfrac></msqrt><mo>=</mo><mo>&#160;</mo><msqrt><mfrac><mn>64</mn><mn>25</mn></mfrac></msqrt><mo>=</mo><mfrac><msqrt><mn>64</mn></msqrt><msqrt><mn>25</mn></msqrt></mfrac><mo>=</mo><mfrac><msqrt><msup><mn>8</mn><mn>2</mn></msup></msqrt><msqrt><msup><mn>5</mn><mn>2</mn></msup></msqrt></mfrac><mo>=</mo><mo>&#160;</mo><mfrac><mn>8</mn><mn>5</mn></mfrac><mo>=</mo><mn>1</mn><mfrac><mn>3</mn><mn>5</mn></mfrac></math></p> <p>c) <math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mfrac><mrow><mn>0</mn><mo>,</mo><mn>25</mn></mrow><mn>9</mn></mfrac></msqrt><mo>=</mo><mo>&#160;</mo><msqrt><mfrac><mn>25</mn><mn>900</mn></mfrac></msqrt><mo>=</mo><mfrac><msqrt><mn>25</mn></msqrt><msqrt><mn>900</mn></msqrt></mfrac><mo>=</mo><mfrac><mn>5</mn><mn>30</mn></mfrac><mo>&#160;</mo><mo>=</mo><mfrac><mn>1</mn><mn>6</mn></mfrac></math></p> <p>d)<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mfrac><mrow><mn>8</mn><mo>,</mo><mn>1</mn></mrow><mrow><mn>1</mn><mo>,</mo><mn>6</mn></mrow></mfrac></msqrt><mo>=</mo><mo>&#160;</mo><msqrt><mfrac><mn>81</mn><mn>16</mn></mfrac></msqrt><mo>=</mo><mfrac><msqrt><mn>81</mn></msqrt><msqrt><mn>16</mn></msqrt></mfrac><mo>=</mo><mfrac><mn>9</mn><mn>4</mn></mfrac></math></p>
Hướng dẫn Giải Bài 28 (trang 18, SGK Toán 9, Tập 1)
GV: GV colearn
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Hướng dẫn Giải Bài 28 (trang 18, SGK Toán 9, Tập 1)
GV: GV colearn