resoudre une equation 2/3y-3y-4=1/5y+1/2
2/3y-3y-4=1/5y+1/2
2/3y-3y-1/5y=1/2+4
-38/15y= 9/2
y= 9/2 : -38/15
= 9/2*-15/38
= -135/76
