Bonjour
1) x + 1/4 = 3x - 3/5
x-3x=-3/5-1/4
-2x=(-3*4-1*5)/20
-2x= -17/20
-40x=-17
x=-17/-40=0.425
2) x/2 + 3 = 4x -5
x/2-4x=-5-3
x/2-8x/2=-8
-7x=-16
x=-16/-7
x= 2.285
3) 2x-3/7=x/3+2/5
2x-x/3=2/5+3/7
6x/3-x/3=14/35+15/35
5x/3= 29/35
175x= 105
x= 105/175
x= 0.6 à vérifier les calculs!!!