Question
Answer
$$(7-i)\cdot(2+3i)=-3i^2+19i+14$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(7-i)\cdot(2+3i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}14+21i-2i-3i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-3i^2+19i+14\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{7-i}\right) $ by each term in $ \left( 2+3i\right) $. $$ \left( \color{blue}{7-i}\right) \cdot \left( 2+3i\right) = 14+21i-2i-3i^2 $$ |
| ② | Combine like terms: $$ 14+ \color{blue}{21i} \color{blue}{-2i} -3i^2 = -3i^2+ \color{blue}{19i} +14 $$ |
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