## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$6(a+2)(a-2)$
Factoring the $GCF= 6$, the given expression, $6a^2-24 ,$ is equivalent to \begin{array}{l} 6(a^2-4) \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, $6(a^2-4) ,$ is \begin{array}{l} 6(a+2)(a-2) \end{array}