\(\left|x+1\right|-3=0\)
\(\Rightarrow\left|x+1\right|=0+3\)
\(\Rightarrow\left|x+1\right|=3.\)
\(\Rightarrow\left[{}\begin{matrix}x+1=3\\x+1=-3\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3-1\\x=\left(-3\right)-1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=2\\x=-4\end{matrix}\right.\)
Vậy \(x\in\left\{2;-4\right\}.\)
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