Expanding the expression, we get:

(x^2-1)(x^2+x+1)(x^2-x-1)
= (x^4 + x^3 + x^2 - x^3 - x^2 - x + x^2 + x - 1)(x^2-x-1)
= (x^4 + x - 1)(x^2-x-1)
= x^6 - x^5 - x^4 + x^3 + x^2 - x^2 + x - 1
= x^6 - x^5 - x^4 + x^3 + x - 1