J’ai besoin d’aide svp pour l’exercice 4

Bonjour,

6x - 9 = 12 - 3x

6x + 3x = 12 + 9

9x = 21

x = 21/9

x = 7/3

a. 2x - 3 = 4 - x

2x + x = 4 + 3

3x = 7

x = 7/3 → Oui

b. 2x - 3 = 6 - x

2x + x = 6 + 3

3x = 9

x = 9/3

x = 3 → Non

c. 6x + 3x = 12 + 9

9x = 21

x = 21/9

x = 7/3 → Oui

d. 9x - 9 = 12

9x = 12 + 9

9x = 21

x = 21/9

x = 7/3 → Oui