for [tex]ax^2+bx+c[/tex]
if a≠1 then
first seee if you can undsitribute a
ifyou can't
use the ac method
multiply a and c
find 2 numbers that add to b and multiply to get ac
split b into that
group
undistribute
undistribute
so
[tex]4x^2-7x-15[/tex]
ac=4*-15=-60
what 2 numbers multiply to get -60 and add to get -7?
5 and -12
split b up into -12 and 5
[tex]4x^2-12x+5x-15[/tex]
group
[tex](4x^2-12x)+(5x-15)[/tex]
undistribute
[tex]4x(x-3)+5(x-3)[/tex]
undistribute
[tex](4x+5)(x-3)[/tex]
