(y+4)/5+y+6=(y+8)/2-(y+4)/3
乘以30得6(y+4)+30y+180=15(y+8)-10(y+4)
6y+24+30y+180=15y+120-10y-40
6y+30y-15y+10y=120-40-24-180
31y=-124
y=-4