\(\sqrt{x-y+z}=\sqrt{x}-\sqrt{y}+\sqrt{z}\)
ĐKXĐ : \(x\ge0;y\ge0;z\ge0\)
pt \(\Leftrightarrow\sqrt{x-y+z}+\sqrt{y}=\sqrt{x}+\sqrt{z}\)
\(\Leftrightarrow x-y+z+y+2\sqrt{y\left(x-y+z\right)}=x+z+2\sqrt{xz}\)
\(\Leftrightarrow\sqrt{xy-y^2+yz}=\sqrt{xz}\)
\(\Leftrightarrow xy-y^2+yz-xz=0\)
\(\Leftrightarrow y\left(x-y\right)-z\left(x-y\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=y;ztuyy\\y=z;xtuyy\end{matrix}\right.\)
KL...