Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{2}{4+\sqrt{10}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{2}{4+\sqrt{10}}\frac{4-\sqrt{10}}{4-\sqrt{10}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{8-2\sqrt{10}}{16-4\sqrt{10}+4\sqrt{10}-10} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{8-2\sqrt{10}}{6} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}\frac{4-\sqrt{10}}{3}\end{aligned} $$ | |
| ① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ 4- \sqrt{10}} $$. |
| ② | Multiply in a numerator. $$ \color{blue}{ 2 } \cdot \left( 4- \sqrt{10}\right) = \color{blue}{2} \cdot4+\color{blue}{2} \cdot- \sqrt{10} = \\ = 8- 2 \sqrt{10} $$ Simplify denominator. $$ \color{blue}{ \left( 4 + \sqrt{10}\right) } \cdot \left( 4- \sqrt{10}\right) = \color{blue}{4} \cdot4+\color{blue}{4} \cdot- \sqrt{10}+\color{blue}{ \sqrt{10}} \cdot4+\color{blue}{ \sqrt{10}} \cdot- \sqrt{10} = \\ = 16- 4 \sqrt{10} + 4 \sqrt{10}-10 $$ |
| ③ | Simplify numerator and denominator |
| ④ | Divide both numerator and denominator by 2. |