2分之x+y=4分之y+3 2(x+y)=y+32x+2y=y+32x+y=3-----(3)2分之x+1=5分之x+y5(x+1)=2(x+y)5x+5=2x+2y3x-2y=-5-----(4)(3)×2+(4)7x=1x=1/7将x=1/7带入(3)2/7+y=3y=19/7