resourdre les equation -4 -x = 0 -9 -8x = 15 -21 = x +7 - 3x 1 demie -x = 5 sur 2

bonsoir

- 4 - x = 0
- x = 4
x = - 4

- 9 - 8 x = -15
- 8 x = - 15 + 9
- 8 x = - 6
x = 6/8 = 3/4

- 21 = x + 7 - 3x
- 21 - 7 = - 3 x + x
- 28  = - 2 x
x = 28/2 = 14

1/2 - x = 5/2
1/2 - 2 x /2 = 5/2
1 - 2 x = 5
-  2 x = 5 - 1
- 2 x = 4
x = - 2