If A = 2x - 7x^{2} 3 and B = 4x^{2} - 12x, what is A + B?
A: -3x^{2} 10x 3
B: 3x^{2} - 10x 3
C: -3x^{2} - 10x 3
D: 6x^{2} - 7x - 9

Relax