Réponses

  • Omnes
  • Modérateur confirmé
2014-03-10T00:36:07+01:00
Salut,

A)

4x + 2 = 3x + 5

4x - 3x = 5 - 2
x = 3

B )
(x + 5)/(2x) = 3
(x+5) / 2x - 3 = 0
(x+5)/2x - (3*2x)/2x = 0
(x+5 - 6x) / 2x = 0

(5 -5x) / 2x = 0
2x ≠0
x ≠ 0

5-5x = 0
5 = 5x
x = 1

C)


x/5+(x+3)/2 = 4 
2x / 10 + 5(x+3) /10 - 40/10 = 0
(2x + 5x + 15 - 40 )/ 10 =0
(7x - 25) / 10 = 0
7x - 25 = 0
7x = 25
x = 25/7

Bonne soirée !