Answer
$x^2-2x-80$
Work Step by Step
Using the Distributive Property and then combining similar terms, the given expression, $
(x-10)(x+8)
,$ is equivalent to
\begin{array}{l}\require{cancel}
x(x)+x(8)-10(x)-10(8)
\\\\=
x^2+8x-10x-80
\\\\=
x^2-2x-80
.\end{array}