For 
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
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
group
undistribute
undistribute
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
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
group
undistribute
undistribute