`|x^2 +|6x-2||= x^2+4`
`= x^2 + | 6x - 2| = x^2 + 4`
`= |6x - 2| = x^2 + 4 x^2`
`= |6x - 2| = (x^2 - x^2) + 4`
`= |6x -2 | = 4`
$\Rightarrow\left[{}\begin{matrix}6x-2=4\\6x-2=-4\end{matrix}\right.$
$\Rightarrow\left[{}\begin{matrix}6x=6\\6x=-2\end{matrix}\right.$
$\Rightarrow\left[{}\begin{matrix}x=1\\x=\dfrac{-1}{3}\end{matrix}\right.$
`\text{Vậy x =1;}` `\text{x =}` `-1/3`
