Giải phương trình |2x+1|=|x+1|

* Hướng dẫn giải

$\begin{array}{l}\left|2x+1\right|=\left|x+1\right|\\ \Rightarrow \left[\begin{array}{l}2x+1=x+1\\ 2x+1=-x-1\end{array}\right.\iff \left[\begin{array}{l}x=0\\ x=-\frac{2}{3}\end{array}\right.S=\left\{0;\frac{-2}{3}\right\}\end{array}$