若|2x+y-3|+(x-1/2y)^2=0,求4x^2-2y-y^2-1的值

若|2x+y-3|+(x-1/2y)^2=0,则有：2x+y-3=0且x- 1/2*y=0即有：2x+y=3且2x-y=0所以：4x²-2y-y²-1=4x²-（y²+2y+1）=4x²-(y+1)²=(2x+y+1)(2x-y-1)=(3+1)*(0-1)=4*(-1)=-4