bonjour
x
x - 4
3 ( x - 4 ) = 3 x - 12
3 x - 12 + 5
= 3 x - 7
si on prend 2
3 * 2 - 7 = 6 - 7 = - 1
3 x - 7 = 2
3 x = 2 + 7
3 x = 9
x = 3
il faut choisir 3
- 2 z + 15 = 4 z + 2
- 2 z - 4 z = 2 - 15
- 6 z = - 13
z = 13/6
5 x - 15 = 28
5 x = 28 + 15
5 x = 43
x = 43/5
- 7 x = 2 x - 8
- 7 x - 2 x = - 8
- 9 x = - 8
x = 8/9