Question
Answer
$$(-2-4i)(-2i)=4i-8$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(-2-4i)(-2i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}4i+8i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}4i-8\end{aligned} $$ | |
| ① | $$ \left( \color{blue}{-2-4i}\right) \cdot -2i = 4i+8i^2 $$ |
| ② | $$ 8i^2 = 8 \cdot (-1) = -8 $$ |
This page was created using
Complex Expression calculator