问题描述：
：Which of the following polynomials is in descending powers of
A,4-2x+3x^2-x^3
B,4+3x^2+2x-x^3
C,-x^3+3x^2+2x+4
D,-x^3+2x+3x^2+4
A,4-2x+3x^2-x^3
B,4+3x^2+2x-x^3
C,-x^3+3x^2+2x+4
D,-x^3+2x+3x^2+4
问题解答：
我来补答展开全文阅读