Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{4}{-3+\sqrt{2}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{4}{-3+\sqrt{2}}\frac{-3-\sqrt{2}}{-3-\sqrt{2}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{-12-4\sqrt{2}}{9+3\sqrt{2}-3\sqrt{2}-2} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{-12-4\sqrt{2}}{7}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ -3- \sqrt{2}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ 4 } \cdot \left( -3- \sqrt{2}\right) = \color{blue}{4} \cdot-3+\color{blue}{4} \cdot- \sqrt{2} = \\ = -12- 4 \sqrt{2} $$ Simplify denominator. $$ \color{blue}{ \left( -3 + \sqrt{2}\right) } \cdot \left( -3- \sqrt{2}\right) = \color{blue}{-3} \cdot-3\color{blue}{-3} \cdot- \sqrt{2}+\color{blue}{ \sqrt{2}} \cdot-3+\color{blue}{ \sqrt{2}} \cdot- \sqrt{2} = \\ = 9 + 3 \sqrt{2}- 3 \sqrt{2}-2 $$ |
③ | Simplify numerator and denominator |