Exercices 1)2/3(9x+1)=3x-2 2)1/5(25-5x)=(4/5-x)1/4 Merci d'avance

Bonjour,

1)2/3(9x+1)=3x-2

18/3x + 2/3 = 3x - 2

6x + 2/3 = 3x - 2

6x - 3x = - 2 - 2/3

3x = - 6/3 - 2/3

3x = - 8/3

9x/3 = - 8/3

9x = - 8

x = - 8/9

2)1/5(25-5x)=(4/5-x)1/4

25/5 - 5/5x = 4/20 - 1/4x

5 - x = 1/5 - 1/4x

- x + 1/4x = 1/5 - 5

- 4/4x + 1/4x = 1/5 - 25/5

- 3/4x = - 24/5

- 15/20x = - 96/20

- 15x = - 96

x = 96/15

x = 6,4.