x^3-x^2+x+1 =x^3+x^2+x-1
Subtract x^3, x from each side
-x^2 + x + 1 = x^2 - 1
-x^2 + 1 = x^2 - 1 rearange as
0 = 2x^2 - 2
2x^2 - 2 = 0 divide through by 2
x^2 - 1 = 0 factor
y = (1)^3 + (1)^2 + 1 - 1 =
(x + 1) ( x - 1) = 0
Set each factor to 0 and solve for x
And x = 1 or x = -1
And using x^3+x^2+x-1
y = (1)^3 + (1)^2 + 1 - 1 = 2
y = (-1)^3 + (-1)^2 - 1 - 1 = -2
So the solutions are (1, 2) and (-1. -2)