(х-1)(х^2+х+1)-х^2(х-8) при х= -1/4

Question

(х-1)(х^2+х+1)-х^2(х-8) при х= -1/4

Answer 1

(x-1)(x²+x+1)-x²(x-8)=x³-1-x³+8x²=8x²-1=8*(-1/4)²-1=8/16-1=1/2-1=-1/2.