ĐKXĐ: \(\left|x\right|\ge\sqrt{3}\)
\(\Leftrightarrow x^2-3=\left(x^2-3\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2-3=0\\x^2-3=1\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x^2=3\\x^2=4\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=\pm\sqrt{3}\\x=\pm2\end{matrix}\right.\)