先化简再求值:(x+2)(x2-2x+4)+(x-1)(x2+x+1),其中x=-2/3

问题描述:

先化简再求值:(x+2)(x2-2x+4)+(x-1)(x2+x+1),其中x=-2/3

(x+2)(x2-2x+4)+(x-1)(x2+x+1)
=x^3+8+x^3-1
=2x^3+7 x=-2/3
=-16/27+7
=173/27