x^7-x^5y^2 x^2y^5-b^7等于多少

问题描述:

x^7-x^5y^2 x^2y^5-b^7等于多少

x^7-x^5y^2
=x^5(x^2-y^2)
=x^5(x+y)(x-y)
x^2y^5-y^7
=y^5(x^2-y^2)
=y^5(x+y)(x-y)