-{-[-(-x^2)-y^2]}
问题描述：
-{-[-(-x^2)-y^2]}
答
=x^2-y^2=(x+y)(x-y)
答
(x+y)(x-y)
答
原式＝（x＋y）（x－y）
答
答：
-{-[-(-x^2)-y^2]}
=-(-x^2)-y^2
=x^2-y^2
=(x-y)(x+y)
答
-{-[-(-x^2)-y^2]}
=-(-x^2)-y^2
=x^2-y^2
=(x+y)(x-y)
希望能帮到您,