Bonjour,
x + 8 = 5 => x=-3
x - 2 = 7 => x= 9
-21 = 5 + x => x= -26
7 = 7 + x => x= 0
-8 - x = - 5 => x= -3
2 x - 5 = - 1=> x= 4/2=2
3 = - 12 + 3 x => x= 15/3=5
- 6 - 5 x = - 9=> x= 3/5
20 = 4 x - 3 => x= 23/4
1,5 x + 6 = - 3 => x= -9/1.5= -6
4 - 3 x = -8 => x = -12/-3= 4
-2,5 x + 5 = - 10 => x= -15/-2.5= 6