x²+y²+5/4-2x-y=0
(x²-2x+1)+(y²-y+1/4)=0
(x-1)²+(y-1/2)²=0
所以x-1=0,y-1/2=0
x=1,y=1/2
所以原式=(1+1/2)分之(1*1/2)=3分之1