原式等价于10(x+1)=5(y+3)=4(x+y)
10(x+1)=5(y+3)可得2x-y=1 5(y+3)=4(x+y)可得4x-y=15
解得x=7 y=13 x+2y+3=36 3x+2y+1=48 两式相除得0.75