Question
Answer
$$(8-7i)\cdot(-7+8i)=-56i^2+113i-56$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(8-7i)\cdot(-7+8i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-56+64i+49i-56i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-56i^2+113i-56\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{8-7i}\right) $ by each term in $ \left( -7+8i\right) $. $$ \left( \color{blue}{8-7i}\right) \cdot \left( -7+8i\right) = -56+64i+49i-56i^2 $$ |
| ② | Combine like terms: $$ -56+ \color{blue}{64i} + \color{blue}{49i} -56i^2 = -56i^2+ \color{blue}{113i} -56 $$ |
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