Question
Answer
$$(7+2i)(2i-2)=4i^2+10i-14$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(7+2i)(2i-2)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}14i-14+4i^2-4i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}4i^2+10i-14\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{7+2i}\right) $ by each term in $ \left( 2i-2\right) $. $$ \left( \color{blue}{7+2i}\right) \cdot \left( 2i-2\right) = 14i-14+4i^2-4i $$ |
| ② | Combine like terms: $$ \color{blue}{14i} -14+4i^2 \color{blue}{-4i} = 4i^2+ \color{blue}{10i} -14 $$ |
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