Question
Answer
$$(1+2i)\cdot(3-2i)=-4i^2+4i+3$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(1+2i)\cdot(3-2i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}3-2i+6i-4i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-4i^2+4i+3\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{1+2i}\right) $ by each term in $ \left( 3-2i\right) $. $$ \left( \color{blue}{1+2i}\right) \cdot \left( 3-2i\right) = 3-2i+6i-4i^2 $$ |
| ② | Combine like terms: $$ 3 \color{blue}{-2i} + \color{blue}{6i} -4i^2 = -4i^2+ \color{blue}{4i} +3 $$ |
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