Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{4}{2\sqrt{3}\sqrt{7}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{4}{2\sqrt{3}\sqrt{7}}\frac{\sqrt{21}}{\sqrt{21}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{4\sqrt{21}}{42} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{ 4 \sqrt{ 21 } : \color{blue}{ 2 } } { 42 : \color{blue}{ 2 }} \xlongequal{ } \\[1 em] & \xlongequal{ }\frac{2\sqrt{21}}{21}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ \sqrt{21}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ 4 } \cdot \sqrt{21} = 4 \sqrt{21} $$ Simplify denominator. $$ \color{blue}{ 2 \sqrt{21} } \cdot \sqrt{21} = 42 $$ |
③ | Divide numerator and denominator by $ \color{blue}{ 2 } $. |