Hướng dẫn Giải Bài 62 (trang 33, SGK Toán 9, Tập 1)

Hướng dẫn giải Bài 62 (Trang 33 SGK Toán 9, Tập 1)

Bài 62 (Trang 33 SGK Toán 9, Tập 1): Rút gọn các biểu thức sau: a)<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>1</mn><mn>2</mn></mfrac><msqrt><mn>48</mn></msqrt><mo> </mo><mo>-</mo><mo> </mo><mn>2</mn><msqrt><mn>75</mn></msqrt><mo> </mo><mo>-</mo><mfrac><msqrt><mn>33</mn></msqrt><msqrt><mn>11</mn></msqrt></mfrac><mo> </mo><mo>+</mo><mn>5</mn><mo> </mo><msqrt><mn>1</mn><mfrac><mn>1</mn><mn>3</mn></mfrac></msqrt></math> ; b) <math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>150</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>1</mn><mo>,</mo><mn>6</mn></msqrt><mo>.</mo><msqrt><mn>60</mn></msqrt><mo>+</mo><mo> </mo><mn>4</mn><mo>,</mo><mn>5</mn><msqrt><mn>2</mn><mfrac><mn>2</mn><mn>3</mn></mfrac></msqrt><mo>-</mo><msqrt><mn>6</mn></msqrt></math>; c) <math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced><mrow><msqrt><mn>28</mn></msqrt><mo> </mo><mo>-</mo><mo> </mo><mn>2</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>7</mn></msqrt></mrow></mfenced><msqrt><mn>7</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>84</mn></msqrt></math>; d) <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mfenced><mrow><msqrt><mn>6</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>5</mn></msqrt></mrow></mfenced><mrow><mn>2</mn><mo> </mo></mrow></msup><mo> </mo><mo>-</mo><mo> </mo><msqrt><mn>120</mn></msqrt></math>.   Hướng dẫn giải: <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">a</mi><mo>)</mo><mo> </mo><mfrac><mn>1</mn><mn>2</mn></mfrac><msqrt><mn>48</mn><mo> </mo></msqrt><mo>-</mo><mo> </mo><mn>2</mn><msqrt><mn>75</mn></msqrt><mo> </mo><mo>-</mo><mo> </mo><mfrac><msqrt><mn>33</mn></msqrt><msqrt><mn>11</mn></msqrt></mfrac><mo> </mo><mo>+</mo><mo> </mo><mn>5</mn><msqrt><mn>1</mn><mfrac><mn>1</mn><mn>3</mn></mfrac></msqrt><mo> </mo><mo>=</mo><mo> </mo><mfrac><mn>1</mn><mn>2</mn></mfrac><msqrt><mn>16</mn><mo>.</mo><mn>3</mn><mo> </mo></msqrt><mo> </mo><mo>-</mo><mo> </mo><mn>2</mn><msqrt><mn>75</mn></msqrt><mo> </mo><mo>-</mo><mfrac><msqrt><mn>33</mn></msqrt><msqrt><mn>11</mn></msqrt></mfrac><mo> </mo><mo>+</mo><mo> </mo><mn>5</mn><msqrt><mfrac><mrow><mn>4</mn><mo>.</mo><mn>4</mn></mrow><mrow><mn>3</mn><mo>.</mo><mn>3</mn></mrow></mfrac></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mfrac><mn>4</mn><mn>2</mn></mfrac><msqrt><mn>3</mn></msqrt><mo> </mo><mo>-</mo><mo> </mo><mn>2</mn><mo>.</mo><mn>5</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><mfrac><mrow><mn>5</mn><mo>.</mo><mn>2</mn></mrow><mn>3</mn></mfrac><msqrt><mn>3</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mfrac><mn>4</mn><mn>2</mn></mfrac><msqrt><mn>3</mn></msqrt><mo> </mo><mo>-</mo><mo> </mo><mn>2</mn><mo>.</mo><mn>5</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><mfrac><mrow><mn>5</mn><mo>.</mo><mn>2</mn></mrow><mn>3</mn></mfrac><msqrt><mn>3</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mn>2</mn><msqrt><mn>3</mn><mo> </mo></msqrt><mo>-</mo><mo> </mo><mn>10</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo> </mo><mo>-</mo><msqrt><mn>3</mn></msqrt><mo>+</mo><mo> </mo><mfrac><mn>10</mn><mn>3</mn></mfrac><msqrt><mn>3</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mo>-</mo><mn>9</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><mfrac><mn>10</mn><mn>3</mn></mfrac><msqrt><mn>3</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mfenced><mrow><mo>-</mo><mn>9</mn><mo> </mo><mo>+</mo><mfrac><mn>10</mn><mn>3</mn></mfrac></mrow></mfenced><msqrt><mn>3</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mo>-</mo><mfrac><mn>17</mn><mn>3</mn></mfrac><msqrt><mn>3</mn></msqrt></math>   <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">b</mi><mo>)</mo><mo> </mo><msqrt><mn>150</mn></msqrt><mo> </mo><mo>+</mo><mo> </mo><msqrt><mn>1</mn><mo>,</mo><mn>6</mn></msqrt><mo>.</mo><msqrt><mn>60</mn></msqrt><mo> </mo><mn>4</mn><mo>,</mo><mn>5</mn><msqrt><mn>2</mn><mfrac><mn>2</mn><mn>3</mn></mfrac></msqrt><mo>-</mo><msqrt><mn>6</mn><mo> </mo></msqrt><mo>=</mo><mo> </mo><msqrt><mn>25</mn><mo>.</mo><mn>6</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>1</mn><mo>,</mo><mn>6</mn></msqrt><mo>.</mo><msqrt><mn>60</mn></msqrt><mo> </mo><mo>+</mo><mo> </mo><mn>4</mn><mo>,</mo><mn>5</mn><msqrt><mn>2</mn><mfrac><mn>2</mn><mn>3</mn></mfrac></msqrt><mo> </mo><mo>-</mo><msqrt><mn>6</mn></msqrt><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mn>5</mn><msqrt><mn>6</mn><mo> </mo></msqrt><mo> </mo><mo>+</mo><msqrt><mn>16</mn><mo>.</mo><mn>6</mn></msqrt><mo> </mo><mo>+</mo><mn>4</mn><mo>,</mo><mn>5</mn><mo>.</mo><mfrac><mn>1</mn><mn>3</mn></mfrac><msqrt><msup><mn>3</mn><mn>2</mn></msup><mo> </mo><mfrac><mrow><mn>4</mn><mo>.</mo><mn>2</mn></mrow><mn>3</mn></mfrac></msqrt><mo> </mo><mo>-</mo><msqrt><mn>6</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mn>5</mn><msqrt><mn>6</mn></msqrt><mo> </mo><mo>+</mo><mn>4</mn><msqrt><mn>6</mn></msqrt><mo> </mo><mo>+</mo><mn>4</mn><mo>,</mo><mn>5</mn><mo>.</mo><mfrac><mn>2</mn><mn>3</mn></mfrac><msqrt><mn>6</mn></msqrt><mo>-</mo><msqrt><mn>6</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mn>9</mn><msqrt><mn>6</mn></msqrt><mo> </mo><mo>+</mo><mn>3</mn><msqrt><mn>6</mn></msqrt><mo> </mo><mo>-</mo><msqrt><mn>6</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mn>11</mn><msqrt><mn>6</mn></msqrt></math>   <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">c</mi><mo>)</mo><mo> </mo><mfenced><mrow><msqrt><mn>28</mn><mo> </mo></msqrt><mo> </mo><mo>-</mo><mn>2</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>7</mn></msqrt></mrow></mfenced><msqrt><mn>7</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>84</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mfenced><mrow><msqrt><mn>4</mn><mo>.</mo><mn>7</mn></msqrt><mo> </mo><mo>-</mo><mn>2</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>7</mn></msqrt></mrow></mfenced><msqrt><mn>7</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>4</mn><mo>.</mo><mn>21</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mfenced><mrow><mn>2</mn><msqrt><mn>7</mn><mo> </mo></msqrt><mo>-</mo><mn>2</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>7</mn></msqrt></mrow></mfenced><msqrt><mn>7</mn><mo> </mo></msqrt><mo>+</mo><mn>2</mn><msqrt><mn>21</mn><mo> </mo></msqrt><mo>=</mo><mo> </mo><mfenced><mrow><mn>3</mn><msqrt><mn>7</mn></msqrt><mo>-</mo><mo> </mo><mn>2</mn><msqrt><mn>7</mn></msqrt></mrow></mfenced><msqrt><mn>7</mn></msqrt><mo> </mo><mo>+</mo><mn>2</mn><msqrt><mn>7</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mn>3</mn><mo>.</mo><mn>7</mn><mo> </mo><mo>-</mo><mo> </mo><mn>2</mn><msqrt><mn>21</mn></msqrt><mo> </mo><mo>+</mo><mn>2</mn><msqrt><mn>21</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mn>21</mn><mo>.</mo></math>   <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">d</mi><mo>)</mo><mo> </mo><msup><mfenced><mrow><msqrt><mn>6</mn></msqrt><mo> </mo><mo>+</mo><msqrt><mn>5</mn></msqrt></mrow></mfenced><mn>2</mn></msup><mo> </mo><mo>-</mo><msqrt><mn>120</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msup><mfenced><msqrt><mn>6</mn></msqrt></mfenced><mn>2</mn></msup><mo> </mo><mo>+</mo><mn>2</mn><msqrt><mn>6</mn></msqrt><mo>.</mo><msqrt><mn>5</mn></msqrt><mo> </mo><mo>+</mo><msup><mfenced><msqrt><mn>5</mn></msqrt></mfenced><mn>2</mn></msup><mo> </mo><mo>-</mo><msqrt><mn>4</mn><mo>.</mo><mn>30</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mo> </mo><mo>=</mo><mo> </mo><mn>6</mn><mo> </mo><mo>+</mo><mo> </mo><mn>2</mn><msqrt><mn>30</mn></msqrt><mo> </mo><mo>+</mo><mn>5</mn><mo> </mo><mo>-</mo><mn>2</mn><msqrt><mn>30</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mn>11</mn></math>