设x/y=a,则y/x=1/a∵(2x-y)/3y=y/x∴2x/3y-1/3=y/x∴2a/3-1/3=1/a两边同时乘以3a2a²-a=3a²-a/2=3/2(a-1/4)²=3/2+1/16(a-1/4)²=25/16a-1/4=±5/4a=(1±5)/4a=3/2或-1