Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{\sqrt{5}}{6-\sqrt{5}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{\sqrt{5}}{6-\sqrt{5}}\frac{6+\sqrt{5}}{6+\sqrt{5}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{6\sqrt{5}+5}{36+6\sqrt{5}-6\sqrt{5}-5} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{6\sqrt{5}+5}{31}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 6 + \sqrt{5}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ \sqrt{5} } \cdot \left( 6 + \sqrt{5}\right) = \color{blue}{ \sqrt{5}} \cdot6+\color{blue}{ \sqrt{5}} \cdot \sqrt{5} = \\ = 6 \sqrt{5} + 5 $$ Simplify denominator. $$ \color{blue}{ \left( 6- \sqrt{5}\right) } \cdot \left( 6 + \sqrt{5}\right) = \color{blue}{6} \cdot6+\color{blue}{6} \cdot \sqrt{5}\color{blue}{- \sqrt{5}} \cdot6\color{blue}{- \sqrt{5}} \cdot \sqrt{5} = \\ = 36 + 6 \sqrt{5}- 6 \sqrt{5}-5 $$ |
③ | Simplify numerator and denominator |