Bonjour
1)
28x - 5 = 10x + 3
28x - 10x = 3 + 5
18x = 8
x = 8/18
x = 4/9
2)
7 (x + 5) = 8x - 3
7x + 35 = 8x - 3
7x - 8x = - 3 - 35
- x = - 38
x = 38
3)
1/4 (x + 7) = 3/2 (x - 7)
1/4x + 7/4 = 3/2x - 21/2
1/4x - 3/2x = - 21/2 - 7/4
1/4x - 6/4x = - 42/4 - 7/4
- 5/4x = - 49/4.
- 5x = - 49
x = 49/5
4)
2/3 (x - 7) = 1/3 (2x + 10)
2/3x - 14/3 = 2/3x + 10/3
2/3x - 2/3x = 10/3 + 14/3
0x = 24/3 → Impossible
5)
x (x + 1) = 0
x = 0 ou x + 1 = 0
x = - 1
