Question
Answer
$$(-7+8i)(-2i+8)=-16i^2+78i-56$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(-7+8i)(-2i+8)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}14i-56-16i^2+64i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-16i^2+78i-56\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{-7+8i}\right) $ by each term in $ \left( -2i+8\right) $. $$ \left( \color{blue}{-7+8i}\right) \cdot \left( -2i+8\right) = 14i-56-16i^2+64i $$ |
| ② | Combine like terms: $$ \color{blue}{14i} -56-16i^2+ \color{blue}{64i} = -16i^2+ \color{blue}{78i} -56 $$ |
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