Answer
$5(t+4)(t-4)$
Work Step by Step
Factoring the $GCF=
5
$, the given expression, $
5t^2-80
,$ is equivalent to
\begin{array}{l}
5(t^2-16)
\end{array}
Using $x^2-y^2=(x+y)(x-y)$ or the factoring of the difference of 2 squares, then the factored form of the expression, $
5(t^2-16)
,$ is
\begin{array}{l}
5(t+4)(t-4)
\end{array}