Let f(x)=x^2-16 and g(x)=x^2-6x+8.
What is (f/g)(x)?
Hint: You will factor using difference of squares and a=1 methods
(x^2-16) / (x^2-6x+8) =
(x-4)(x+4) / ( x -4)(x-2) (x cannnot equal 4)
The numerator and denominator (x-4)'s cancel and you are left with:
(x+4) /(x-2) x cannot equl 4 or 2