Answer
{$20,24$}
Work Step by Step
Using the rules for the factoring of trinomials, we obtain:
$n^{2}-44n+480=0$
$n^{2}-20n-24n+480=0$
$n(n-20)-24(n-20)=0$
$(n-20)(n-24)=0$
$(n-20)=0$ and $(n-24)=0$
$n=20$ and $n=24$
Therefore, the solution set is {$20,24$}.