The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.8092\\[1 em]x_2 &= 4.4046+3.5677i\\[1 em]x_3 &= 4.4046-3.5677i \end{aligned} $$Polynomial $ x^3-8x^2+25x+26 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.