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