Answer
$(n+4)(n+5)$.
Work Step by Step
The given polynomial is
$=n^2+9n+20$
Standard form is $x^2+bx+c$.
We have $b=9$ and $c=20$.
$b$ and $c$ is positive.
Factor pair of $20$, whose sum is $9$:-
$4,5$
The values of $p$ and $q$ are $4$ and $5$.
Hence, the factor of the polynomial is $(n+p)(n+q)=(n+4)(n+5)$.
Check:-
$=(n+4)(n+5)$
$=n^2+5n+4n+20$
$=n^2+9n+20$
True.
