Bonjour,

4x + 5 = 13

4x = 13 - 5

4x = 8

x = 8/4 = 2  

-2x + 7 = - 3

-2x = - 3 - 7

-2x = - 10

x = -10/(-2) = 5

5x - 1 = 2x + 8

5x - 2x = 8 + 1

3x = 9

x = 9/3 = 3

3(x - 1) + 4x = 5 - (2x - 7)

3x - 3 + 4x  = 5 - 2x + 7

7x - 3 = - 2x + 12

tu termines ?