#### Answer

$x^2+x-20$

#### Work Step by Step

Make a table.
$\ \ \ \ \ \ \underline{|\ \ \ \ \ \ \ x\ \ \ \ \ \ |\ \ \ \ \ \ \ \ 5\ \ \ \ \ |}$
$\ \ \ x\ |\ \ \ \ \ \ \ \ x^2\ \ \ |\ \ \ \ \ \ \ \ 5x\ \ \ |$
$-4\ |\ \ \ -4x\ \ \ |\ \ \ -20\ \ \ |$
The product is
$x^2+5x-4x-20$
Combine like terms.
$x^2+x-20$