x^2+y^2+5/4=2x+y 移项,得 x^-2x+y^-y+5/4=0 所以x^-2x+1+y^-y+1/4=0 所以(x-1)^+(y-1/2)^=0 因为(x-1)^≥0,(y-1/2)^≥0 所以x-1=0,y-1/2=0 故x=1,y=1/2 所以x+y=3/2