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| 1. |
Write whether 2√45+3√20÷2√5 |
| Answer» {tex}\\frac{2\\sqrt{45\\;\\;}+3\\sqrt{20}}{2\\sqrt5}{/tex}{tex}\\text{=}\\frac{\\displaystyle2\\sqrt{5\\times9}+3\\sqrt{5\\times4}}{2\\sqrt5}{/tex}{tex}=\\frac{6\\sqrt5+6\\sqrt5}{2\\sqrt5}{/tex}{tex}=\\frac{\\displaystyle12\\sqrt5}{2\\sqrt5}{/tex}{tex}=6=\\frac61{/tex}Hence the given number can be written in the form of {tex}\\frac pq{/tex} where p and q are integers.So the given expression is a rational number. | |