The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= \frac{ 1 }{ 2 }+\frac{\sqrt{ 3 }}{ 6 }i\\[1 em]x_2 &= \frac{ 1 }{ 2 }- \frac{\sqrt{ 3 }}{ 6 }i \end{aligned} $$The solutions of $ -3x^2+3x-1 = 0 $ are: $ x = \dfrac{ 1 }{ 2 }+\dfrac{\sqrt{ 3 }}{ 6 }i ~ \text{and} ~ x = \dfrac{ 1 }{ 2 }-\dfrac{\sqrt{ 3 }}{ 6 }i$.
You can use step-by-step quadratic equation solver to see a detailed explanation on how to solve this quadratic equation.