Simplify: (x+3)2−6x(x+3)^2 - 6x(x+3)2−6x.
x2+9x^2 + 9x2+9
x2+6x+9x^2 + 6x + 9x2+6x+9
x2−9x^2 - 9x2−9
x2+3x^2 + 3x2+3