#### Answer

$12+2i$

#### Work Step by Step

Removing the grouping symbols and then combining the real parts and the imaginary parts, the given expression is equivalent to
\begin{array}{l}\require{cancel}
(9+8i)-(-3+6i)
\\\\=
9+8i+3-6i
\\\\=
(9+3)+(8i-6i)
\\\\=
12+2i
.\end{array}