Question

先化简，在求值，[2x平方-(x+y)(x-y)][(-x-y)(-x+y)+2y平方]，x=-1

先化简，在求值，[2x平方-(x+y)(x-y)][(-x-y)(-x+y)+2y平方]，x=-1，y=-2，全过程

Answer 1

2x的平方-(x+y)(x-y)][(-x-y)(y-x)+2y的平方]
=[2x²-(x²-y²)][-(y+x)(y-x)+2y²]
=[2x²-x²+y²][-(y²-x²)+2y²]
=(x²+y²)(x²+y²)
=25

Answer 2

[2x的平方-(x+y)(x-y)][(-x-y)(y-x)+2y的平方]
=[2x²-(x²-y²)][(x+y)(x-y)+2y²]
=(2x²-x²+y²)(x²-y²+2y²)
=(x²+y²)/(x²+y²)
=1