In order to solve $ \color{blue}{ 2x^{6}-12x^{2}-4x = 0 } $, first we need to factor our $ x $.
$$ 2x^{6}-12x^{2}-4x = x \left( 2x^{5}-12x-4 \right) $$$ x = 0 $ is a root of multiplicity $ 1 $.
The remaining roots can be found by solving equation $ 2x^{5}-12x-4 = 0$.
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using Newton method.