## Elementary Technical Mathematics

$(a+9)(a-7)$
$a^2+2a-63$ has no common monomial factors. =$(\ \ \ \ \ \ \ \ \ )(\ \ \ \ \ \ \ \ \ )$ =$(a\ \ \ \ \ \ \ )(a\ \ \ \ \ \ \ )$ =$(a+\ \ )(a-\ \ )$ The factors of -63 must have dislike signs. =$(a+9)(a-7)$ -7 and 9 have a sum of 2 and a product of -63.