Question
Answer
$$(2+7i)\cdot(-4+6i)=42i^2-16i-8$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(2+7i)\cdot(-4+6i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-8+12i-28i+42i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}42i^2-16i-8\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{2+7i}\right) $ by each term in $ \left( -4+6i\right) $. $$ \left( \color{blue}{2+7i}\right) \cdot \left( -4+6i\right) = -8+12i-28i+42i^2 $$ |
| ② | Combine like terms: $$ -8+ \color{blue}{12i} \color{blue}{-28i} +42i^2 = 42i^2 \color{blue}{-16i} -8 $$ |
This page was created using
Complex Expression calculator