Question
Answer
$$\dfrac{5+\sqrt{12}}{\sqrt{12}-\sqrt{8}}=\dfrac{5\sqrt{3}+5\sqrt{2}+6+2\sqrt{6}}{2}$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{5+\sqrt{12}}{\sqrt{12}-\sqrt{8}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{5+\sqrt{12}}{\sqrt{12}-\sqrt{8}}\frac{\sqrt{12}+\sqrt{8}}{\sqrt{12}+\sqrt{8}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{10\sqrt{3}+10\sqrt{2}+12+4\sqrt{6}}{12+4\sqrt{6}-4\sqrt{6}-8} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{10\sqrt{3}+10\sqrt{2}+12+4\sqrt{6}}{4} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}\frac{5\sqrt{3}+5\sqrt{2}+6+2\sqrt{6}}{2}\end{aligned} $$ | |
| ① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ \sqrt{12} + \sqrt{8}} $$. |
| ② | Multiply in a numerator. $$ \color{blue}{ \left( 5 + \sqrt{12}\right) } \cdot \left( \sqrt{12} + \sqrt{8}\right) = \color{blue}{5} \cdot \sqrt{12}+\color{blue}{5} \cdot \sqrt{8}+\color{blue}{ \sqrt{12}} \cdot \sqrt{12}+\color{blue}{ \sqrt{12}} \cdot \sqrt{8} = \\ = 10 \sqrt{3} + 10 \sqrt{2} + 12 + 4 \sqrt{6} $$ Simplify denominator. $$ \color{blue}{ \left( \sqrt{12}- \sqrt{8}\right) } \cdot \left( \sqrt{12} + \sqrt{8}\right) = \color{blue}{ \sqrt{12}} \cdot \sqrt{12}+\color{blue}{ \sqrt{12}} \cdot \sqrt{8}\color{blue}{- \sqrt{8}} \cdot \sqrt{12}\color{blue}{- \sqrt{8}} \cdot \sqrt{8} = \\ = 12 + 4 \sqrt{6}- 4 \sqrt{6}-8 $$ |
| ③ | Simplify numerator and denominator |
| ④ | Divide both numerator and denominator by 2. |
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