Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{10}{6-\sqrt{7}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{10}{6-\sqrt{7}}\frac{6+\sqrt{7}}{6+\sqrt{7}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{60+10\sqrt{7}}{36+6\sqrt{7}-6\sqrt{7}-7} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{60+10\sqrt{7}}{29}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 6 + \sqrt{7}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ 10 } \cdot \left( 6 + \sqrt{7}\right) = \color{blue}{10} \cdot6+\color{blue}{10} \cdot \sqrt{7} = \\ = 60 + 10 \sqrt{7} $$ Simplify denominator. $$ \color{blue}{ \left( 6- \sqrt{7}\right) } \cdot \left( 6 + \sqrt{7}\right) = \color{blue}{6} \cdot6+\color{blue}{6} \cdot \sqrt{7}\color{blue}{- \sqrt{7}} \cdot6\color{blue}{- \sqrt{7}} \cdot \sqrt{7} = \\ = 36 + 6 \sqrt{7}- 6 \sqrt{7}-7 $$ |
③ | Simplify numerator and denominator |