Tap the blue circles to see an explanation.
$$ \begin{aligned}4i\cdot(-2-8i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-8i-32i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-8i+32\end{aligned} $$ | |
① | Multiply $ \color{blue}{4i} $ by $ \left( -2-8i\right) $ $$ \color{blue}{4i} \cdot \left( -2-8i\right) = -8i-32i^2 $$ |
② | $$ -32i^2 = -32 \cdot (-1) = 32 $$ |