# How do you use the factor theorem to determine whether x+1 is a factor of x^3 - x^2 + 3x -3?

If $x - r$ is a factor of a polynomial $P \left(x\right)$ then $P \left(r\right) = 0$.But here
$x - \left(- 1\right)$ is not a factor of ${x}^{3} - {x}^{2} + 3 x - 3$