Answer
$6(2x+3)(2x-3)$
Work Step by Step
Factoring the $GCF=
6
$, the given expression, $
24x^2-54
,$ is equivalent to
\begin{array}{l}
6(4x^2-9)
\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, $
6(4x^2-9)
,$ is
\begin{array}{l}
6(2x+3)(2x-3)
\end{array}