x+y-2=0,求（x²-y²）²-8（x²+y²）的值.

x+y-2=0,求（x²-y²）²-8（x²+y²）的值.
x+y-2=0,求（x²-y²）²-8（x²+y²）的值.

x+y-2=0,求（x²-y²）²-8（x²+y²）的值.
x+y-2=0
x+y=2
（x²-y²）²-8（x²+y²）
=(x+y)²﹙x-y)²-8x²-8y²
=4(x²-2xy+y²)-8x²-8y²
=4x²-8xy-4y²-8x²-8y²
=-4(x²+2xy+y²)
=-4(x+y)²
=-4×2²
=-16