Question
Answer
$$\dfrac{4\sqrt{5}+3\sqrt{2}}{2\sqrt{2}-\sqrt{5}}=\dfrac{11\sqrt{10}+32}{3}$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{4\sqrt{5}+3\sqrt{2}}{2\sqrt{2}-\sqrt{5}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{4\sqrt{5}+3\sqrt{2}}{2\sqrt{2}-\sqrt{5}}\frac{2\sqrt{2}+\sqrt{5}}{2\sqrt{2}+\sqrt{5}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{8\sqrt{10}+20+12+3\sqrt{10}}{8+2\sqrt{10}-2\sqrt{10}-5} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{11\sqrt{10}+32}{3}\end{aligned} $$ | |
| ① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 2 \sqrt{2} + \sqrt{5}} $$. |
| ② | Multiply in a numerator. $$ \color{blue}{ \left( 4 \sqrt{5} + 3 \sqrt{2}\right) } \cdot \left( 2 \sqrt{2} + \sqrt{5}\right) = \color{blue}{ 4 \sqrt{5}} \cdot 2 \sqrt{2}+\color{blue}{ 4 \sqrt{5}} \cdot \sqrt{5}+\color{blue}{ 3 \sqrt{2}} \cdot 2 \sqrt{2}+\color{blue}{ 3 \sqrt{2}} \cdot \sqrt{5} = \\ = 8 \sqrt{10} + 20 + 12 + 3 \sqrt{10} $$ Simplify denominator. $$ \color{blue}{ \left( 2 \sqrt{2}- \sqrt{5}\right) } \cdot \left( 2 \sqrt{2} + \sqrt{5}\right) = \color{blue}{ 2 \sqrt{2}} \cdot 2 \sqrt{2}+\color{blue}{ 2 \sqrt{2}} \cdot \sqrt{5}\color{blue}{- \sqrt{5}} \cdot 2 \sqrt{2}\color{blue}{- \sqrt{5}} \cdot \sqrt{5} = \\ = 8 + 2 \sqrt{10}- 2 \sqrt{10}-5 $$ |
| ③ | Simplify numerator and denominator |
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