Simplify the expression (x2+2x)+(3x2−4x)(x^2 + 2x) + (3x^2 - 4x)(x2+2x)+(3x2−4x).
4x2−2x4x^2 - 2x4x2−2x
4x2+6x4x^2 + 6x4x2+6x
3x2−2x3x^2 - 2x3x2−2x
4x4−2x24x^4 - 2x^24x4−2x2