Answer
$x^2+3x-54$
Work Step by Step
Using the Distributive Property and then combining similar terms, the given expression, $
(x+9)(x-6)
, $ is equivalent to
\begin{array}{l}\require{cancel}
x(x)+x(-6)+9(x)+9(-6)
\\\\=
x^2-6x+9x-54
\\\\=
x^2+3x-54
.\end{array}