Question
Answer
$$(7+i)\cdot(-8+6i)=6i^2+34i-56$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(7+i)\cdot(-8+6i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-56+42i-8i+6i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}6i^2+34i-56\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{7+i}\right) $ by each term in $ \left( -8+6i\right) $. $$ \left( \color{blue}{7+i}\right) \cdot \left( -8+6i\right) = -56+42i-8i+6i^2 $$ |
| ② | Combine like terms: $$ -56+ \color{blue}{42i} \color{blue}{-8i} +6i^2 = 6i^2+ \color{blue}{34i} -56 $$ |
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