## Intermediate Algebra (12th Edition)

$(z-5p)(z+4p)$
$\bf{\text{Solution Outline:}}$ To factor the given expression, $z^2-zp-20p^2 ,$ use the factoring of trinomials in the form $x^2+bx+c.$ $\bf{\text{Solution Details:}}$ In the trinomial expression above, $b= -1 ,\text{ and } c= -20 .$ Using the factoring of trinomials in the form $x^2+bx+c,$ the two numbers whose product is $c$ and whose sum is $b$ are $\left\{ -5,4 \right\}.$ Using these two numbers, the factored form of the expression above is \begin{array}{l}\require{cancel} (z-5p)(z+4p) .\end{array}