ĐKXĐ: \(x\ge-\frac{1}{2}\)
\(\Leftrightarrow x^2-8x+16+2x+1-6\sqrt{2x+1}+9=0\)
\(\Leftrightarrow\left(x-4\right)^2+\left(\sqrt{2x+1}-3\right)^2=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(x-4\right)^2=0\\\left(\sqrt{2x+1}-3\right)^2=0\end{matrix}\right.\) \(\Rightarrow x=4\)