3X(x^2-2x-1)-2x^2(x-3)=多少
问题描述:
3X(x^2-2x-1)-2x^2(x-3)=多少
答
3X(x^2-2x-1)-2x^2(x-3)
=3x^3-6x^2-3x-2x^3+6x^2
=x^3-3x