*nếu có 3 GP thì tốt 
*
\(\left|5x-4\right|=\left|x+2\right|\)
\(\Rightarrow\left[{}\begin{matrix}5x-4=x+2\\5x-4=-x-2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}4x=6\\6x=2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1,5\\x=\dfrac{1}{3}\end{matrix}\right.\)
\(\left|5x-4\right|=\left|x+2\right|\)
\(\Leftrightarrow\left[{}\begin{matrix}5x-4=x+2\\5x-4=-x-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}4x=6\\6x=2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
Vậy tập nghiệm của PT là \(S=\left\{\dfrac{3}{2};\dfrac{1}{3}\right\}\)
