## Elementary Technical Mathematics

$(y+8)(y-9)$
$y^2-y-72$ has no common monomial factors. =$(\ \ \ \ \ \ \ \ \ )(\ \ \ \ \ \ \ \ \ )$ =$(y\ \ \ \ \ \ \ )(y\ \ \ \ \ \ \ )$ =$(y+\ \ )(y-\ \ )$ The factors of -72 must have unlike signs. =$(y+8)(y-9)$ 8 and -9 have a sum of -1 and a product of -72.