Bonsoir,
Il faut tout mettre sous le même dénominateur comme une simple fraction
a. (2x-3)/4=(x+5)/3
(6x - 9)/12 = (4x + 20)/12
6x - 9 = 4x + 20
6x - 4x = 20 + 9
2x = 29
x = 29/2
x = 14,5
b. x+(1/4)=3x-(3/5)
20/20x + 5/20 = 60/20x - 12/20
20x + 5 = 60x - 12
20x - 60x = - 12 - 5
- 40x = - 17
x = 17/40
x = 0,425
c. (x/2)+3=4x-5
x/2 + 6/2 = 8/2x - 10/2
x + 6 = 8x - 10
x - 8x = - 10 - 6
- 7x = - 16
x = 16/7
d. 2x-(3/7)=(x/3)+(2/5)
210/105x - 45/105 = 35/105x + 42/105
210x - 45 = 35x + 42
210x - 35x = 42 + 45
175x = 87
x = 87/175