x^2 + 2x x^2 - 4
------------------- - --------------------
x^2 - 2x - 8 x^2 - 2x - 8
x(x + 2) - (x+2)(x-2)
= --------------------------------------
(x + 2)(x - 4)
(x + 2) ( x - x + 2)
= --------------------------------------
(x + 2)(x - 4)
2
= ------------
(x - 4)
x is NOT equal -2 and 4
