Answer
$(x-5)(x+4)$.
Work Step by Step
The given polynomial is
$=x^2-x-20$
Standard form is $x^2+bx+c$.
We have $b=-1$ and $c=-20$.
$b$ and $c$ is negative.
Factor pair of $-1$, whose sum is $-20$:-
$-5,4$
The values of $p$ and $q$ are $-5$ and $4$.
Hence, the factor of the polynomial is $(x+p)(x+q)=(x-5)(x+4)$.
Check:-
$=(x-5)(x+4)$
$=x^2+4x-5x-20$
$=x^2-x-20$
True.
