Answer
$2r(r-2)(r+17)$
Work Step by Step
$ 2r^{3}+30r^{2}-68r\qquad$...factor out the common term, $2r$
$=2r(r^{2}+15r-34)$
Two factors of $ac=-34$, whose sum is $b=15$
are $-2$ and $17$.
Rewrite the middle term and factor in pairs.
$2r(r^{2}+15r-34)$
$=2r(r^{2}-2r+17r-34)$
$=2r[r(r-2)+17(r-2)]\qquad$...factor out the common binomial factor,$r-2$.
$=2r(r-2)(r+17)$
