[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1,y=2数学：[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1，y=2

[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1,y=2数学：[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1，y=2
[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1,y=2
数学：[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1，y=2

[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1,y=2数学：[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²] 其中x=1，y=2
[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²]
=[2x²-(x²-y²)][(x+y)(x-y)+2y²]
=(2x²-x²+y²)(x²-y²+2y²)
=(x²+y²)²
=(1²+2²)²
=5²
=25

=（x^2+y^2)^2=25

[2x²-(x+y) (x-y)] [(-x-y) (y-x)+2y²]
=[2x²-(x²-y²)][(x+y)(x-y)+2y²]
=(2x²-x²+y²)(x²-y²+2y²)
=(x²+y²)²
=(1²+2²)²
=5²
=25
平方差公式x²-y²=（x+y）（x-y）