Multiplying polynomials < br />
( x-3) (x+3)

We can do this the long way or the short way...you need to know the long way to be able to recognize and use the short cuts..

(x - 3)(x + 3)                  (use distributive property or FOIL)
x(x) + x(3) - 3(x) - 3(3)
x² + 3x - 3x - 9                (combine like terms)
x² - 9                            

IN the future, when you have a polynomial like this and you have the +3, -3...they will always subtract to be 0, so we just multiply the first terms and the last terms to get the answer.

4would have to be the correct answer