Answer
$$(4+4i)\cdot(-2-5i)=-20i^2-28i-8$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(4+4i)\cdot(-2-5i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-8-20i-8i-20i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-20i^2-28i-8\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{4+4i}\right) $ by each term in $ \left( -2-5i\right) $. $$ \left( \color{blue}{4+4i}\right) \cdot \left( -2-5i\right) = -8-20i-8i-20i^2 $$ |
| ② | Combine like terms: $$ -8 \color{blue}{-20i} \color{blue}{-8i} -20i^2 = -20i^2 \color{blue}{-28i} -8 $$ |
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