Answer
$(y+5)(y-4)$
Work Step by Step
$y^2+y-20$ has no common monomial factor.
$=(\ \ \ \ \ \ \ \ )(\ \ \ \ \ \ \ \ )$
$=(y\ \ \ \ \ \ )(y\ \ \ \ \ \ )$
$=(y+\ )(y-\ )$ The factors of -20 must have unlike signs.
$=(y+5)(y-4)$ 5 and -4 have a sum of 1 and a product of -20.
