bonjour
2 x + 9 = 9 x - 5
⇔ 2 x - 9 x = - 5 - 9
⇔ - 7 x = - 14
⇔ x = 2
8 x - 10 = 4 + x
⇔ 8 x - x = 4 + 10
⇔ 7 x = 14
⇔ x = 2
12 x - 5 = 15 x + 6 + 2
⇔ 12 x - 15 x = 8 + 5
⇔ - 3 x = 13
⇔ x = - 13/3
5 x - 2 = 3 x + 12
⇔ 5 x- 3 x = 12 + 2
⇔ 2 x = 14
⇔ x = 7
allez fais le dernier