Answer
$2x^2+3x-20$
Work Step by Step
Using $(a+b)(c+d)=ac+ad+bc+bd$ or the Distributive Property, the given expression, $
(2x-5)(x+4)
,$ is equivalent to
\begin{array}{l}\require{cancel}
2x(x)+2x(4)-5(x)-5(4)
\\\\=
2x^2+8x-5x-20
\\\\=
2x^2+3x-20
.\end{array}