Question

(x+9)(x-9)

is this the same as the FOIL method, I'm lost

Answer 1

yup

Answer 2

the answer is x^2-81

Answer 3

first = x^2
outer = -9x
inner = +9x
last = -81

the outer and inner will be canceld out so the answer is

x^2-81

:-)

Answer 4

That can be recognized as "the difference of squares".. There is a formula..

Answer 5

And you can "foil" it.

Answer 6

(x-a)(x+a) = x^2 - a^2

if you foil it, it will turn out the same because two of the terms end up to cancel...