Answer
$-2q^4-7q^2+15$
Work Step by Step
Removing the grouping symbols and then combining like terms, the given expression, $
(q^4-2q^2+10)-(3q^4+5q^2-5)
,$ simplifies to
\begin{array}{l}\require{cancel}
q^4-2q^2+10-3q^4-5q^2+5
\\\\=
(q^4-3q^4)+(-2q^2-5q^2)+(10+5)
\\\\=
-2q^4-7q^2+15
.\end{array}