Question
Answer
$$(-2i)\cdot(5-2i)-(-4i)(-4i)=-12i^2-10i$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}(-2i)\cdot(5-2i)-(-4i)(-4i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-10i+4i^2-16i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-12i^2-10i\end{aligned} $$ | |
| ① | Multiply $ \color{blue}{-2i} $ by $ \left( 5-2i\right) $ $$ \color{blue}{-2i} \cdot \left( 5-2i\right) = -10i+4i^2 $$ |
| ② | Combine like terms: $$ -10i+ \color{blue}{4i^2} \color{blue}{-16i^2} = \color{blue}{-12i^2} -10i $$ |
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