Question
Answer
$$(7+2i)\cdot(7+2i)=4i^2+28i+49$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(7+2i)\cdot(7+2i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}49+14i+14i+4i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}4i^2+28i+49\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{7+2i}\right) $ by each term in $ \left( 7+2i\right) $. $$ \left( \color{blue}{7+2i}\right) \cdot \left( 7+2i\right) = 49+14i+14i+4i^2 $$ |
| ② | Combine like terms: $$ 49+ \color{blue}{14i} + \color{blue}{14i} +4i^2 = 4i^2+ \color{blue}{28i} +49 $$ |
This page was created using
Complex Expression calculator