Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{9}{8-\sqrt{2}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{9}{8-\sqrt{2}}\frac{8+\sqrt{2}}{8+\sqrt{2}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{72+9\sqrt{2}}{64+8\sqrt{2}-8\sqrt{2}-2} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{72+9\sqrt{2}}{62}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 8 + \sqrt{2}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ 9 } \cdot \left( 8 + \sqrt{2}\right) = \color{blue}{9} \cdot8+\color{blue}{9} \cdot \sqrt{2} = \\ = 72 + 9 \sqrt{2} $$ Simplify denominator. $$ \color{blue}{ \left( 8- \sqrt{2}\right) } \cdot \left( 8 + \sqrt{2}\right) = \color{blue}{8} \cdot8+\color{blue}{8} \cdot \sqrt{2}\color{blue}{- \sqrt{2}} \cdot8\color{blue}{- \sqrt{2}} \cdot \sqrt{2} = \\ = 64 + 8 \sqrt{2}- 8 \sqrt{2}-2 $$ |
③ | Simplify numerator and denominator |