Bonjour,
1)2/3(9x+1)=3x-2
18/3x + 2/3 = 3x - 2
6x + 2/3 = 3x - 2
6x - 3x = - 2 - 2/3
3x = - 6/3 - 2/3
3x = - 8/3
9x/3 = - 8/3
9x = - 8
x = - 8/9
2)1/5(25-5x)=(4/5-x)1/4
25/5 - 5/5x = 4/20 - 1/4x
5 - x = 1/5 - 1/4x
- x + 1/4x = 1/5 - 5
- 4/4x + 1/4x = 1/5 - 25/5
- 3/4x = - 24/5
- 15/20x = - 96/20
- 15x = - 96
x = 96/15
x = 6,4.
