#### Answer

$5z^2-7x+2m$

#### Work Step by Step

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