Question
Answer
$$\dfrac{10\sqrt{45}+15\sqrt{20}}{2\sqrt{5}}=30$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{10\sqrt{45}+15\sqrt{20}}{2\sqrt{5}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{10\sqrt{45}+15\sqrt{20}}{2\sqrt{5}}\frac{\sqrt{5}}{\sqrt{5}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{150+150}{10} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{300}{10} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}} \frac{ 300 : \color{orangered}{ 10 } }{ 10 : \color{orangered}{ 10 }} \xlongequal{ } \\[1 em] & \xlongequal{ }\frac{30}{1} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle5}{\textcircled {5}} } }}}30\end{aligned} $$ | |
| ① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ \sqrt{5}} $$. |
| ② | Multiply in a numerator. $$ \color{blue}{ \left( 10 \sqrt{45} + 15 \sqrt{20}\right) } \cdot \sqrt{5} = \color{blue}{ 10 \sqrt{45}} \cdot \sqrt{5}+\color{blue}{ 15 \sqrt{20}} \cdot \sqrt{5} = \\ = 150 + 150 $$ Simplify denominator. $$ \color{blue}{ 2 \sqrt{5} } \cdot \sqrt{5} = 10 $$ |
| ③ | Simplify numerator and denominator |
| ④ | Divide both the top and bottom numbers by $ \color{orangered}{ 10 } $. |
| ⑤ | Remove 1 from denominator. |
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