Answer
$5r^3+4rs-6r^2$
Work Step by Step
Removing the grouping symbols and then combining like terms, the given expression, $
(7r^3+rs-5r^2)-(2r^3-3rs+r^2)
,$ simplifies to
\begin{array}{l}\require{cancel}
7r^3+rs-5r^2-2r^3+3rs-r^2
\\\\=
(7r^3-2r^3)+(rs+3rs)+(-5r^2-r^2)
\\\\=
5r^3+4rs-6r^2
.\end{array}
