4*x ------ 2 x - 4
(4*x)/(x^2 - 4)
2/(-2 + x) + 2/(2 + x)
2 2 ------ + ----- -2 + x 2 + x
4.0*x/(-4.0 + x^2)
4*x ---------------- (-2 + x)*(2 + x)
4*x/((-2 + x)*(2 + x))