Réponse :

1) 2 x + 3 = x + 5  ⇔ 2 x - x = 5 - 3 ⇔ x = 2

2) 3 x - 5 = 2 x + 9 ⇔ 3 x - 2 x = 9+5 ⇔ x = 14

3) x + 3 = 2 x - 5 ⇔ 2 x - x = 3 + 5 ⇔ x = 8

4) 8 x - 3 = 4 x + 9 ⇔ 8 x - 4 x = 9+3 ⇔ 4 x = 12 ⇔ x = 12/4 = 3

5) 2 x + 2 = 9 - 5 x ⇔ 2 x + 5 x = 9 - 2 ⇔ 7 x = 7 ⇔ x = 7/7 = 1

6) 3 - 2 x = - 5  ⇔ 2 x = 3+5 ⇔ 2 x = 8 ⇔ x = 8/2 = 4

Explications étape par étape