(x的三次方-2x的二次方+x-1)-(x的平方+x-1)
=x^3-2x²+x-1-x²-x+1
=x^3-3x²
=(-3/2)^3-3(-3/2)²
=-27/8-3x9/4
=-27/8-27/4
=-81/8