Question
Answer
$$(-2-i)\cdot(12+8i)=-8i^2-28i-24$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(-2-i)\cdot(12+8i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-24-16i-12i-8i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-8i^2-28i-24\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{-2-i}\right) $ by each term in $ \left( 12+8i\right) $. $$ \left( \color{blue}{-2-i}\right) \cdot \left( 12+8i\right) = -24-16i-12i-8i^2 $$ |
| ② | Combine like terms: $$ -24 \color{blue}{-16i} \color{blue}{-12i} -8i^2 = -8i^2 \color{blue}{-28i} -24 $$ |
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