\(\sqrt{x}\left(\sqrt{x}-4\right)=0\)
\(\left[{}\begin{matrix}\sqrt{x}=0\\\sqrt{x}-4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\\left[{}\begin{matrix}x=16\\x=-16\end{matrix}\right.\end{matrix}\right.\)
\(\sqrt[x-4]{x}=0\Rightarrow\sqrt[x-4]{\left(x\right)^{x-4}}=0^{x-4}\Rightarrow x=0\)