x^4y-7x^2y^2+6-3xy^3-4x^3按字母x的降幂排列和按y的升幂排列,

问题描述:

x^4y-7x^2y^2+6-3xy^3-4x^3按字母x的降幂排列和按y的升幂排列,

x^4y-7x^2y^2+6-3xy^3-4x^3
=x^4y-4x^3-7x^2y^2-3xy^3+6...按x降幂
=-4x^3+x^4y-7x^2y^2-3xy^3+6...按y升幂