Question
Answer
$$\dfrac{3}{5\sqrt{2}-2}=\dfrac{15\sqrt{2}+6}{46}$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{3}{5\sqrt{2}-2}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{3}{5\sqrt{2}-2}\frac{5\sqrt{2}+2}{5\sqrt{2}+2} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{15\sqrt{2}+6}{50+10\sqrt{2}-10\sqrt{2}-4} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{15\sqrt{2}+6}{46}\end{aligned} $$ | |
| ① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 5 \sqrt{2} + 2} $$. |
| ② | Multiply in a numerator. $$ \color{blue}{ 3 } \cdot \left( 5 \sqrt{2} + 2\right) = \color{blue}{3} \cdot 5 \sqrt{2}+\color{blue}{3} \cdot2 = \\ = 15 \sqrt{2} + 6 $$ Simplify denominator. $$ \color{blue}{ \left( 5 \sqrt{2}-2\right) } \cdot \left( 5 \sqrt{2} + 2\right) = \color{blue}{ 5 \sqrt{2}} \cdot 5 \sqrt{2}+\color{blue}{ 5 \sqrt{2}} \cdot2\color{blue}{-2} \cdot 5 \sqrt{2}\color{blue}{-2} \cdot2 = \\ = 50 + 10 \sqrt{2}- 10 \sqrt{2}-4 $$ |
| ③ | Simplify numerator and denominator |
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