#### Answer

$-4m^2+4n^2-7n$

#### Work Step by Step

Removing the grouping symbols and then combining like terms, the given expression, $
(-4m^2+3n^2-5n)-[(3m^2-5n^2+2n)+(-3m^2)+4n^2]
,$ simplifies to
\begin{array}{l}\require{cancel}
-4m^2+3n^2-5n-[3m^2-5n^2+2n-3m^2+4n^2]
\\\\=
-4m^2+3n^2-5n-3m^2+5n^2-2n+3m^2-4n^2
\\\\=
(-4m^2-3m^2+3m^2)+(3n^2+5n^2-4n^2)+(-5n-2n)
\\\\=
-4m^2+4n^2-7n
.\end{array}