Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{6}{8+\sqrt{13}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{6}{8+\sqrt{13}}\frac{8-\sqrt{13}}{8-\sqrt{13}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{48-6\sqrt{13}}{64-8\sqrt{13}+8\sqrt{13}-13} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{48-6\sqrt{13}}{51}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 8- \sqrt{13}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ 6 } \cdot \left( 8- \sqrt{13}\right) = \color{blue}{6} \cdot8+\color{blue}{6} \cdot- \sqrt{13} = \\ = 48- 6 \sqrt{13} $$ Simplify denominator. $$ \color{blue}{ \left( 8 + \sqrt{13}\right) } \cdot \left( 8- \sqrt{13}\right) = \color{blue}{8} \cdot8+\color{blue}{8} \cdot- \sqrt{13}+\color{blue}{ \sqrt{13}} \cdot8+\color{blue}{ \sqrt{13}} \cdot- \sqrt{13} = \\ = 64- 8 \sqrt{13} + 8 \sqrt{13}-13 $$ |
③ | Simplify numerator and denominator |