Bài 6: Biến đổi đơn giản biểu thức chứa căn thức bậc hai
Hướng dẫn giải Bài 45 (Trang 27 SGK Toán 9, Tập 1)
<p><strong>Bài 45 (Trang 27 SGK Toán 9, Tập 1):</strong></p>
<p>So sánh:</p>
<p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">a</mi><mo>)</mo><mo> </mo><mn>3</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mi>và</mi><mo> </mo><msqrt><mn>12</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi mathvariant="normal">b</mi><mo>)</mo><mo> </mo><mn>7</mn><mo> </mo><mi>và</mi><mo> </mo><mn>3</mn><msqrt><mn>5</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi mathvariant="normal">c</mi><mo>)</mo><mo> </mo><mfrac><mn>1</mn><mn>3</mn></mfrac><msqrt><mn>51</mn></msqrt><mo> </mo><mi>và</mi><mo> </mo><mfrac><mn>1</mn><mn>5</mn></mfrac><msqrt><mn>150</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mi mathvariant="normal">d</mi><mo>)</mo><mo> </mo><mfrac><mn>1</mn><mn>2</mn></mfrac><msqrt><mn>6</mn></msqrt><mo> </mo><mi>và</mi><mo> </mo><mn>6</mn><msqrt><mfrac><mn>1</mn><mn>2</mn></mfrac></msqrt><mo>.</mo></math></p>
<p> </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>a</mi><mo>)</mo><mo> </mo><msqrt><mn>12</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><msup><mn>2</mn><mn>2</mn></msup><mo>.</mo><mn>3</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><mn>2</mn><msqrt><mn>3</mn></msqrt><mo> </mo><mo><</mo><mo> </mo><mn>3</mn><msqrt><mn>3</mn></msqrt><mo>.</mo></math></p>
<p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo> </mo><mn>7</mn><mo> </mo><mo>=</mo><mo> </mo><msqrt><mn>49</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mn>3</mn><msqrt><mn>5</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><msup><mn>3</mn><mn>2</mn></msup><mo>.</mo><mn>5</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><mn>45</mn></msqrt><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>V</mi><mi>ì</mi><mo> </mo><msqrt><mn>49</mn></msqrt><mo> </mo><mo>></mo><mo> </mo><msqrt><mn>45</mn></msqrt><mo> </mo><mo> </mo><mi>n</mi><mi>ê</mi><mi>n</mi><mo> </mo><mn>7</mn><mo> </mo><mo>></mo><mo> </mo><mn>3</mn><msqrt><mn>5</mn></msqrt></math></p>
<p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">c</mi><mo>)</mo><mo> </mo><mfrac><mn>1</mn><mn>3</mn></mfrac><msqrt><mn>51</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><msup><mfenced><mfrac><mn>1</mn><mn>3</mn></mfrac></mfenced><mn>2</mn></msup><mo>.</mo><mn>51</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><mfrac><mn>17</mn><mn>3</mn></mfrac><mo> </mo></msqrt><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mfrac><mn>1</mn><mn>5</mn></mfrac><msqrt><mn>150</mn><mo> </mo></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><msup><mfenced><mfrac><mn>1</mn><mn>5</mn></mfrac></mfenced><mn>2</mn></msup><mo>.</mo><mn>150</mn></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><mn>6</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>Vì</mi><mo> </mo><msqrt><mfrac><mn>17</mn><mn>3</mn></mfrac></msqrt><mo> </mo><mo><</mo><mo> </mo><msqrt><mn>6</mn></msqrt><mo> </mo><mo> </mo><mi>nên</mi><mo> </mo><mfrac><mn>1</mn><mn>3</mn></mfrac><msqrt><mn>51</mn></msqrt><mo> </mo><mo><</mo><mo> </mo><mfrac><mn>1</mn><mn>5</mn></mfrac><msqrt><mn>150</mn></msqrt></math></p>
<p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">d</mi><mo>)</mo><mo> </mo><mfrac><mn>1</mn><mn>2</mn></mfrac><msqrt><mn>6</mn><mo> </mo></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><msup><mfenced><mfrac><mn>1</mn><mn>2</mn></mfrac></mfenced><mn>2</mn></msup><mo>.</mo><mn>6</mn></msqrt><mo> </mo><mo> </mo><mo>=</mo><mo> </mo><msqrt><mfrac><mn>3</mn><mn>2</mn></mfrac></msqrt><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mn>6</mn><msqrt><mfrac><mn>1</mn><mn>2</mn></mfrac></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><msup><mn>6</mn><mrow><mn>2</mn><mo> </mo></mrow></msup><mo>.</mo><mfrac><mn>1</mn><mn>2</mn></mfrac></msqrt><mo> </mo><mo>=</mo><mo> </mo><msqrt><mn>18</mn></msqrt><mo>;</mo><mspace linebreak="newline"/><mspace linebreak="newline"/><mi>Vì</mi><mo> </mo><msqrt><mfrac><mn>3</mn><mn>2</mn></mfrac></msqrt><mo> </mo><mo><</mo><mo> </mo><msqrt><mn>18</mn></msqrt><mo> </mo><mo> </mo><mi>nên</mi><mo> </mo><mfrac><mn>1</mn><mn>2</mn></mfrac><msqrt><mn>6</mn></msqrt><mo> </mo><mo><</mo><mo> </mo><mn>6</mn><msqrt><mfrac><mn>1</mn><mn>2</mn></mfrac></msqrt><mo>.</mo></math></p>
Hướng dẫn Giải Bài 45 (trang 27, SGK Toán 9, Tập 1)
GV: 
GV colearn
GV colearn
Xem lời giải bài tập khác cùng bài
Video hướng dẫn giải bài tập
Hướng dẫn Giải Bài 45 (trang 27, SGK Toán 9, Tập 1)
GV: GV colearn
GV colearn