Answer
$7q^3-9q^2-8q+9$
Work Step by Step
Removing the grouping symbols and then combining like terms, the given expression, $
(3q^3-9q^2+6)+(4q^3-8q+3)
,$ evaluates to
\begin{array}{l}\require{cancel}
3q^3-9q^2+6+4q^3-8q+3
\\\\=
(3q^3+4q^3)-9q^2-8q+(6+3)
\\\\=
7q^3-9q^2-8q+9
.\end{array}
