Answer
The two factors of the polynomial can be multiplied together. If the resulting polynomial is not the same as the polynomial originally, then there was a mistake.
Work Step by Step
Example: $x^2-6x-16$ divided by $x+2$ is $x-8$.
$(x+2)(x-8)$:
First: $x*x$
Outside: $x*-8$
Inside: $2*x$
Last: $2*-8$
$x*x+x*-8+2*x+2*-8$
$x^2-8x+2x-16$
$x^2-6x-16$
