Answer
$-2z^3+7z^2-11z+4$
Work Step by Step
Using the Distributive Property, the product of the given expression, $
(2z-1)(-z^2+3z-4)
,$ is
\begin{array}{l}\require{cancel}
2z(-z^2)+2z(3z)+2z(-4)-1(-z^2)-1(3z)-1(-4)
\\\\=
-2z^3+6z^2-8z+z^2-3z+4
\\\\=
-2z^3+(6z^2+z^2)+(-8z-3z)+4
\\\\=
-2z^3+7z^2-11z+4
.\end{array}