Bonsoir,
2x - 5 = 4x + 3
2x - 5 - 2x = 4x + 3 - 2x
-5 = 2x + 3
-5 - 3 = 2x + 3 - 3
-8 = 2x
2x / 2 = -8 / 2
x = -4
Vérification : 2(-4) - 5 = -8 - 5 = -13
4(-4) + 3 = -16 + 3 = -13
3(x + 4) - 7 = 15 - 2x
3x + 12 - 7 = 15 - 2x
3x + 5 = 15 - 2x
3x + 5 - 3x = 15 - 2x - 3x
5 = 15 - 5x
5 - 15 = 15 - 5x - 15
-10 = -5x
-5x / -5 = -10 / -5
x = 2
Vérification : 3(2 + 4) - 7 = 6 + 12 - 7 = 18 - 7 = 11
15 - 2(2) = 15 - 4 = 11
