{(x-y)(x+y)}的三次方
=(x^2-y^2)^3
=(x^2-y^2)^2(x^2-y^2)
=(x^4-2x^2y^2+y^4)(x^2-y^2)
=x^6-x^4y^2-2x^4y^2+2x^2y^4+x^2y^4-y^6
=x^6-3x^4y^2+3x^2y^4-y^6
追问{(x-y)(x+y)}的三次方为什么
=(x^2-y^2)^3
谢了
追答{(x-y)(x+y)}的三次方
={(x-y)(x+y)}^3
=(x^2+xy-xy-y^2)^3
=(x^2-y^2)^3