Réponse:
5x - 8 = 3
5x = 3 + 8
5x = 11
x = 11/5
6x + 13 = - 11
6x = - 11 - 13
6x = - 24
x = - 24 / 6
x = - 4
8x + 5 = 7x - 2
8x + 5 - 7x = - 2
x + 5 = - 2
x = - 2 - 5
x = - 7
- 5x + 12 = 4x - 15
- 5x + 12 - 4x = - 15
- 9x + 12 = - 15
- 9x = - 15 - 12
- 9x = - 27
x = - 27/-9
x = 3