$ |2x+1|=3$
⇒ \(\left[ \begin{array}{l}2x+1=3\\2x+1=-3\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}2x=3-1\\2x=-3-1\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}2x=2\\2x=-4\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=1\\x=-2\end{array} \right.\)
Vậy $x=-2$ hoặc $x=1$
