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

$-5(4a+3)(4a-3)$
Factoring the negative $GCF= -5$, the given expression, $-80a^2+45 ,$ is equivalent to \begin{array}{l} -5(16a^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, $-5(16a^2-9) ,$ is \begin{array}{l} -5(4a+3)(4a-3) \end{array}