bonjour

3 x + 5 = 0

3 x = - 5

x = - 5 /3

8 x + 14 = 0

8 x = - 14

x = - 14/8 = - 7 /4

7 x - 9 = 5 x + 11

7 x -  5 x = 11 + 9

2 x = 20

x = 10

3 x - 9 = 8 - 7 x

3 x + 7 x = 8 + 9

10 x = 17

x = 1.7

Réponse :

Bonjour

Explications étape par étape :

A = 3x + 5 = 0

3x = -5

x = -5/3

B = 8x + 14 = 0

8x = -14

x = -14/8 = -7/4

C= 7x -9 = 5x + 11

7x - 5x = 9 + 11

2x = 20

x = 20/2 = 10

D = 3x - 9 = 8 -7x

3x + 7x = 9 + 8

10x = 17

x = 17/10