đk: \(x\ge0;y-z\ge0;z-x\ge0\Leftrightarrow y\ge z\ge x\ge0\)
Ta có: \(pt\Leftrightarrow2\sqrt{x}+2\sqrt{y-z}+2\sqrt{z-x}=x+y-z+z-x+3\)
\(\Leftrightarrow\left(\sqrt{x}-1\right)^2+\left(\sqrt{y-z}-1\right)^2+\left(\sqrt{z-x}-1\right)^2=0\)
\(\Leftrightarrow\hept{\begin{cases}\sqrt{x}=1\\\sqrt{y-z}=1\\\sqrt{z-x}=1\end{cases}\Leftrightarrow\hept{\begin{cases}x=1\\y=3\\z=2\end{cases}\left(tm\text{đ}k\right)}}\)