Bonjour,
a) 3x + 16 = 8x - 9
3x - 8x = - 9 - 16
- 5x = - 25
x = 25/5
x = 5
b) 9 (x + 3) = 2 (x + 66)
9x + 27 = 2x + 132
9x - 2x = 132 - 27
7x = 105
x = 105/7
x = 15
c) 3 (x + 7) + 5 (x - 1) - 4 (x + 6) = 0
3x + 21 + 5x - 5 - 4x - 24 = 0
3x + 5x - 4x = - 21 + 5 + 24
4x = 8
x = 8/4
x = 2.
