The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 2.6943\\[1 em]x_2 &= -1.3609 \end{aligned} $$The solutions of $ 6x^2-8x-22 = 0 $ are: $ x = \dfrac{ 2 }{ 3 }-\dfrac{\sqrt{ 37 }}{ 3 } ~ \text{and} ~ x = \dfrac{ 2 }{ 3 }+\dfrac{\sqrt{ 37 }}{ 3 }$.
You can use step-by-step quadratic equation solver to see a detailed explanation on how to solve this quadratic equation.