The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 14\\[1 em]x_2 &= -2 \end{aligned} $$Step 1:
Get rid of fractions by multipling equation by $ \color{blue}{ 2 } $.
$$ \begin{aligned} \frac{1}{2}x^2-6x-14 & = 0 ~~~ / \cdot \color{blue}{ 2 } \\[1 em] x^2-12x-28 & = 0 \end{aligned} $$Step 2:
The solutions of $ x^2-12x-28 = 0 $ are: $ x = -2 ~ \text{and} ~ x = 14$.
You can use step-by-step quadratic equation solver to see a detailed explanation on how to solve this quadratic equation.