将多项式-4x^2+5x-8-x^4+2x^3按字母降次幂排列；把多项式-3ab+4b^4-6a^5-4a^2b^2按字母升次幂排列
问题描述：
将多项式-4x^2+5x-8-x^4+2x^3按字母降次幂排列；把多项式-3ab+4b^4-6a^5-4a^2b^2按字母升次幂排列
答
(1)-4x^2+5x-8-x^4+2x^3=-x^4+2x^3-4x^2+5x-8
(2)-3ab+4b^4-6a^5-4a^2b^2=4b^4-3ab-4a^2b^2-6a^5