The root of polynomial $ p(x) $ is:
$$ \begin{aligned}x &= \frac{ 10001 }{ 8 } \end{aligned} $$Step 1:
Combine like terms:
$$ 10001 \color{blue}{-26139x} + \color{blue}{26131x} = \color{blue}{-8x} +10001 $$Step 2:
$$ \begin{aligned} -8x+10001 & = 0 \\[1 em] -8 \cdot x & = -10001 \\[1 em] x & = - \frac{ 10001 }{ -8 } \\[1 em] x & = \frac{ 10001 }{ 8 } \end{aligned} $$