The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -2.1038+2.6574i\\[1 em]x_2 &= -2.1038-2.6574i\\[1 em]x_3 &= -2.8962+0.8672i\\[1 em]x_4 &= -2.8962-0.8672i \end{aligned} $$Polynomial $ x^4+10x^3+45x^2+105x+105 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.