The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -1.3779\\[1 em]x_2 &= 0.4389+1.0084i\\[1 em]x_3 &= 0.4389-1.0084i \end{aligned} $$Step 1:
Get rid of fractions by multipling equation by $ \color{blue}{ 6 } $.
$$ \begin{aligned} x^3+\frac{1}{2}x^2+\frac{5}{3} & = 0 ~~~ / \cdot \color{blue}{ 6 } \\[1 em] 6x^3+3x^2+10 & = 0 \end{aligned} $$Step 2:
Polynomial $ 6x^3+3x^2+10 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.