Question
Answer
$$(-1+3i)\cdot(8-9i)=-27i^2+33i-8$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(-1+3i)\cdot(8-9i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-8+9i+24i-27i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-27i^2+33i-8\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{-1+3i}\right) $ by each term in $ \left( 8-9i\right) $. $$ \left( \color{blue}{-1+3i}\right) \cdot \left( 8-9i\right) = -8+9i+24i-27i^2 $$ |
| ② | Combine like terms: $$ -8+ \color{blue}{9i} + \color{blue}{24i} -27i^2 = -27i^2+ \color{blue}{33i} -8 $$ |
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