(x+y)^2×(x-y)^2=?

(x+y)^2=x^2+2xy+y^2
(x-y)^2=x^2-2xy+y^2

(x+y)^2×(x-y)^2

=(x^2+y^2+2xy)*(x^2+y^2-2xy)

=x^4+y^4+2x^2y^2-4x^2y^2

=x^4+y^4-2x^2y^2

不懂发消息问我.

（x^2-y^2)^2
相信我的答案是最简洁最完美的答案了。

4x^4+4y^4-2x^2y^2

(x+y)^2×(x-y)^2=[(x+y)(x-y)]^2
=(x^2-y^2)
=x^4+y^4-2x^2y^2