The roots of polynomial $ p(m) $ are:
$$ \begin{aligned}m_1 &= 3.5616\\[1 em]m_2 &= -0.5616 \end{aligned} $$The solutions of $ m^2-3m-2 = 0 $ are: $ m = \dfrac{ 3 }{ 2 }-\dfrac{\sqrt{ 17 }}{ 2 } ~ \text{and} ~ m = \dfrac{ 3 }{ 2 }+\dfrac{\sqrt{ 17 }}{ 2 }$.
You can use step-by-step quadratic equation solver to see a detailed explanation on how to solve this quadratic equation.