Answer:
3x - x + 3 - 9 = 6
3x - x + 3 = 6 +9
2x +3 = 15
2x = 15 - 3
2x = 12
x= 12/2
x= 6
Rules - When the side changes , sign changes .for ex (-9) on changing side (from left to right ) becomes plus 9
