Question
Answer
$$18-40i-(-9+2i)=-42i+27$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}18-40i-(-9+2i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}18-40i+9-2i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-42i+27\end{aligned} $$ | |
| ① | Remove the parentheses by changing the sign of each term within them. $$ - \left( -9+2i \right) = 9-2i $$ |
| ② | Combine like terms: $$ \color{blue}{18} \color{red}{-40i} + \color{blue}{9} \color{red}{-2i} = \color{red}{-42i} + \color{blue}{27} $$ |
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