How do you do the foil method with polynomials?

Step-by-step:

For example,

(x+4) (x-4) (x-3)

group the first two and do foil like normal ignoring the " (x-3) "

You should end up with the answer x^2-16

Now multiply (x^2-16) with (x-3)

that answer should be x^3-3x^2-16x+48