bonsoir,
(1-x) - (3+x)=7
1 - x - 3 - x = 7
- 2 x = 7 - 1 + 3
- 2 x = 9
x = - 9/2
2(3-x)+4(x-2)=0
6 - 2 x + 4 x - 8 = 0
2 x = 8 - 6
2 x = 2
x = 1
4(3-7x)=6(x-1/3)
12 - 28 x = 6 x - 6 /3
- 28 x - 6 x = - 2 - 12
- 34 x = - 14
x = 14/34 = 7/17
3(5-x/3)=7/3+12(1/6-x/4)
15 - 3 x / 3 = 7 /3 + 12 /6 - 12 x / 4
15 - x = 7 /3 + 2 - 3 x
- x + 3 x = 7 /3 - 15 + 2
- 3 x / 3 + 9 x / 3 = 7 /3 - 45/3 + 6 /3
6 x = - 32
x = - 32/6 = - 16/3
continues
