Which equation shows a valid step in solving (3/2)x-6 + (3/2)x+6 = 0?
1) (3/2)x-6 + (3/2)x+6 = 0
2) (3/2)x-6 + (3/2)x+6 = 0
3) (3/2)x-6 + (3/2)x+6 = 0
4) (3/2)x-6 + (3/2)x+6 = 0