(x²-2x+1)+(y²-6y+9)=0(x-1)²+(y-3)²=0所以x-1=0,y-3=0x=1,y=3所以原式=4x⁴-4y²-4x⁴+4x²y-y²=4x²y-5y²=4*1*3-5*9=-33