Tap the blue circles to see an explanation.
$$ \begin{aligned}\sqrt{-175}& \xlongequal{ }\sqrt{175}\cdot i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}} \sqrt{ 25 \cdot 7 } i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}} \sqrt{ 25 } \cdot \sqrt{ 7 } i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}5\sqrt{7}i\end{aligned} $$ | |
① | Factor out the largest perfect square of 175. ( in this example we factored out $ 25 $ ) |
② | Rewrite $ \sqrt{ 25 \cdot 7 } $ as the product of two radicals. |
③ | The square root of $ 25 $ is $ 5 $. |