Answer
$-2x^3+x^2+2x-3$
Work Step by Step
Removing the grouping symbols, then the given expression, $
(-4x^2+2x)-(-5x^2+2x^3+3)
$, is equivalent to
\begin{array}{l}
-4x^2+2x+5x^2-2x^3-3
.\end{array}
By combining like terms, then
\begin{array}{l}
-2x^3+(-4x^2+5x^2)+2x-3
\\\\=
-2x^3+x^2+2x-3
.\end{array}