ĐKXĐ: \(x\ge\frac{1}{4}\)
\(\Leftrightarrow\sqrt{5x+1}=3\sqrt{x}+\sqrt{4x-1}\)
\(\Leftrightarrow5x+1=9x+4x-1+6\sqrt{x\left(4x-1\right)}\)
\(\Leftrightarrow4x-1+3\sqrt{4x-1}=0\)
\(\Leftrightarrow\sqrt{4x-1}\left(\sqrt{4x-1}+3\right)=0\)
\(\Leftrightarrow\sqrt{4x-1}=0\Rightarrow x=\frac{1}{4}\)