The roots of polynomial $ p(t) $ are:
$$ \begin{aligned}t_1 &= 0.4995\\[1 em]t_2 &= -1.9044\\[1 em]t_3 &= 0.2025+4.1808i\\[1 em]t_4 &= 0.2025-4.1808i \end{aligned} $$Polynomial $ 3t^4+3t^3+48t^2+75t-50 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.