2 3*x - 12
3*x^2 - 1*12
1*(x + 2)*(x - 2)
(1*(x + 2))*(x - 2)
-12.0 + 3.0*x^2
/ 2\ 3*\-4 + x /
3*(-4 + x^2)
3*(-2 + x)*(2 + x)