Bài 6: Biến đổi đơn giản biểu thức chứa căn thức bậc hai
Hướng dẫn giải Bài 43 (Trang 27 SGK Toán 9, Tập 1)
<p><strong>B&agrave;i 43 (trang 27, SGK To&aacute;n 9, Tập 1):</strong></p> <p>Viết c&aacute;c số hoặc biểu thức dưới dấu căn th&agrave;nh c&aacute;c dạng t&iacute;ch rồi đưa thừa số ra ngo&agrave;i dấu căn.</p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><msqrt><mn>54</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi>b</mi><mo>)</mo><mo>&#160;</mo><msqrt><mn>108</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi>c</mi><mo>)</mo><mo>&#160;</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>1</mn><msqrt><mn>20000</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi>d</mi><mo>)</mo><mo>&#160;</mo><mo>-</mo><mn>0</mn><mo>.</mo><mn>05</mn><msqrt><mn>28800</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi>e</mi><mo>)</mo><mo>&#160;</mo><msqrt><mn>7</mn><mo>.</mo><mn>63</mn><mo>.</mo><msup><mi>a</mi><mrow><mn>2</mn><mo>&#160;</mo></mrow></msup></msqrt><mo>.</mo></math></p> <p>&nbsp;</p> <p><strong><span style="text-decoration: underline;"><em>Hướng dẫn giải:</em></span></strong></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">a</mi><mo>)</mo><mo>&#160;</mo><msqrt><mn>54</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><msqrt><msup><mn>3</mn><mn>2</mn></msup><mo>.</mo><mn>6</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>3</mn><msqrt><mn>6</mn></msqrt><mo>.</mo></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">b</mi><mo>)</mo><mo>&#160;</mo><msqrt><mn>108</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><msqrt><msup><mn>6</mn><mn>2</mn></msup><mo>.</mo><mn>3</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>6</mn><msqrt><mn>3</mn></msqrt><mo>.</mo></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">c</mi><mo>)</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>1</mn><msqrt><mn>20000</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>.</mo><msqrt><msup><mn>100</mn><mn>2</mn></msup><mo>.</mo><mn>2</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>10</mn><msqrt><mn>2</mn></msqrt><mo>.</mo></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">d</mi><mo>)</mo><mo>&#160;</mo><mo>-</mo><mn>0</mn><mo>,</mo><mn>05</mn><msqrt><mn>28800</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mn>0</mn><mo>,</mo><mn>05</mn><msqrt><msup><mn>120</mn><mn>2</mn></msup><mo>.</mo><mn>2</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mn>6</mn><msqrt><mn>2</mn></msqrt><mo>.</mo></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">e</mi><mo>)</mo><mo>&#160;</mo><msqrt><mn>7</mn><mo>.</mo><mn>63</mn><mo>.</mo><msup><mi mathvariant="normal">a</mi><mn>2</mn></msup></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><msqrt><msup><mn>7</mn><mn>2</mn></msup><mo>.</mo><msup><mn>3</mn><mn>2</mn></msup><mo>.</mo><msup><mi mathvariant="normal">a</mi><mn>2</mn></msup></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>7</mn><mo>.</mo><mn>3</mn><mo>.</mo><mfenced open="|" close="|"><mi mathvariant="normal">a</mi></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>21</mn><mfenced open="|" close="|"><mi mathvariant="normal">a</mi></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close=""><mtable columnalign="left"><mtr><mtd><mn>21</mn><mo>&#160;</mo><mi>n&#7871;u</mi><mo>&#160;</mo><mi mathvariant="normal">a</mi><mo>&#160;</mo><mo>&#8805;</mo><mo>&#160;</mo><mn>0</mn></mtd></mtr><mtr><mtd><mo>-</mo><mn>21</mn><mo>&#160;</mo><mi>n&#7871;u</mi><mo>&#160;</mo><mi mathvariant="normal">a</mi><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mn>0</mn></mtd></mtr></mtable></mfenced></math></p>
Hướng dẫn Giải Bài 43 (trang 27, SGK Toán 9, Tập 1)
GV: GV colearn
Xem lời giải bài tập khác cùng bài
Video hướng dẫn giải bài tập
Hướng dẫn Giải Bài 43 (trang 27, SGK Toán 9, Tập 1)
GV: GV colearn