# How do you simplify 9i+9(5-3i)?

$45 - 18 i$
What is required here is to $\textcolor{b l u e}{\text{distribute the bracket and collect like terms}}$
$\Rightarrow 9 i + 9 \left(5 - 3 i\right) = 9 i + 45 - 27 i = 45 - 18 i$