X intercepts are when y = 0, set the equation equal to zero and solve:
0 = -x^3 +x^2 + x -1
-x^3 + x^2 = -x
-x + x = 0
0-1 = -1
The first one is (-1,0)
Because the equation contains squares the answer could also be opposite, so the other answer would be (1,0)
The two answers are (-1,0) (1,0)
