trouver x 3x-5=x+7 trouver x -2x-4=8-6x

3x - 5 = x + 7
3x - x = 7 + 5
2x = 12
x = 12/2
x = 6

- 2x - 4 = 8 - 6x
- 2x + 6x = 8 + 4
4x = 12
x = 12/4
x = 3