(-y^2)乘多少等于y^5

Question

(-y^2)乘多少等于y^5

Answer 1

因为x^5-y^5=(x-y)(x^4+x^3y+x^2y^2+xy^3+y^4)
x^3-y^3=(x-y)(x^2+xy+y^2)
所以(x^5-y^5)/(x^3-y^3)=(x^4+x^3y+x^2y^2+xy^3+y^4)/(x^2+xy+y^2)
所以(x^3-y^3)*[(x^4+x^3y+x^2y^2+xy^3+y^4)/(x^2+xy+y^2)]=x^5-y^5