Question
Answer
$$(-1+7i)\cdot(-9+2i)=14i^2-65i+9$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(-1+7i)\cdot(-9+2i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}9-2i-63i+14i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}14i^2-65i+9\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{-1+7i}\right) $ by each term in $ \left( -9+2i\right) $. $$ \left( \color{blue}{-1+7i}\right) \cdot \left( -9+2i\right) = 9-2i-63i+14i^2 $$ |
| ② | Combine like terms: $$ 9 \color{blue}{-2i} \color{blue}{-63i} +14i^2 = 14i^2 \color{blue}{-65i} +9 $$ |
This page was created using
Complex Expression calculator