\(\dfrac{2}{5}-\left|\dfrac{1}{2}-x\right|=6\)
\(\Leftrightarrow\left|\dfrac{1}{2}-x\right|=\dfrac{2}{5}-6\)
\(\Leftrightarrow\left|\dfrac{1}{2}-x\right|=-\dfrac{28}{5}\)( vô lý do \(\left|\dfrac{1}{2}-x\right|\ge0\forall x\))
Vậy \(x\in\left\{\varnothing\right\}\)
\(\Rightarrow\left|\dfrac{1}{2}-x\right|=\dfrac{2}{5}-6=-\dfrac{28}{5}\\ \Rightarrow\left[{}\begin{matrix}\dfrac{1}{2}-x=-\dfrac{28}{5},\forall\dfrac{1}{2}-x\ge0\\\dfrac{1}{2}-x=\dfrac{28}{5},\forall\dfrac{1}{2}-x< 0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{61}{10},\forall x\le\dfrac{1}{2}\left(loại\right)\\x=-\dfrac{51}{10},\forall x>\dfrac{1}{2}\left(loại\right)\end{matrix}\right.\Rightarrow x\in\varnothing\)