=>|2x+1|=|x-1|
=>2x+1=x-1 hoặc 2x+1=1-x
=>x=-2 hoặc x=0
`|2x+1|-|x-1|=0`
`<=>|2x+1|=|x-1|`
`<=>4x^2+4x+1=x^2-2x+1`
`<=>3x^2+6x=0`
`<=>3x(x+2)=0`
`<=>` $\left[\begin{matrix} x=0\\ x=-2\end{matrix}\right.$
\(\left|2x+1\right|-\left|x-1\right|=0\)
\(\Leftrightarrow\)\(\left[{}\begin{matrix}x-1=2x+1\\x-1=-\left(2x+1\right)\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}-x-1=1\\3x-1=-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}-x=2\\3x=0\end{matrix}\right.\) \(\Leftrightarrow x=\left[{}\begin{matrix}-2\\0\end{matrix}\right.\)
