Bonjour,
a) 4x + 7 = 2x + 13
4x - 2x = 13 - 7
2x = 6
x = 6/2
x = 3
b) 3t - 7 = - 2t - 9
3t + 2t = - 9 + 7
5t = - 2
t = - 2/5
c) 4 - 5z = 9z
- 5z - 9z = - 4
- 14z = - 4
z = 4/14
z = 2/7
d) - 3u - 8 = - 7u - 4
- 3u + 7u = - 4 + 8
4u = 4
u = 4/4
u = 1
e) 2y + 5 - 5y = 12 --> Je ne vois pas trop le = ...
2y - 5y = 12 - 5
- 3y = 7
y = - 7/3
f) 3a - 2 + a = 6 + 4a
3a + a - 4a = 6 + 2
0a = 8 --> Impossible
