[tex]f(x) = {x}^{3} - {x}^{2} - x - \frac{1}{8} \\ f( \frac{ - 1}{2})=( { \frac{ - 1}{2} })^{3} - ({ \frac{ - 1}{2} })^{2} - ( \frac{ - 1}{2}) - \frac{1}{8} \\ = \frac{ - 1}{8} - \frac{1}{4} + \frac{1}{2} - \frac{1}{8} \\ = \frac{ - 1 - 2 + 4 - 1}{8} \\ = \frac{0}{8} \\ = 0[/tex]
