Bonjour
a) 2x + 3 = - 7
2x = - 7 - 3
2x = - 10
x = - 10/2
x = - 5
b) 4 - 12x = - 8 - 14x
- 12x + 14x = - 8 - 4
2x = - 12
x = - 12/2
x = - 6
c) 5 (2x + 3) = 15 + x
10x + 15 = 15 + x
10x - x = 15 - 14
9x = 0
x = 0
d) 2/3x = - 4/5
10x = - 8
x = - 8/10
x = - 2/4
e) 7x + 2/5 = 5x - 1/10
7x - 5x = - 1/10 - 4/10
2x = - 5/10
2x = - 1/2
4x = - 1
x = - 1/4.