Có:\(\frac{x}{y+z+2}=\frac{y}{z+x+5}=\frac{z}{x+y-7}=\frac{x+y+z}{2\left(x+y+z\right)}\)\(=\frac{1}{2}=x+y+z\)
\(\Rightarrow x=\frac{1}{2}-\left(y+z\right)\)\(\Leftrightarrow y+z=\frac{1}{2}-x\)
*\(\frac{x}{\frac{3}{2}-x}=\frac{1}{2}\)\(\Rightarrow2x=\frac{3}{2}-x\Leftrightarrow x=\frac{1}{2}\)
*\(\frac{y}{\frac{11}{2}-y}=\frac{1}{2}\)=>\(y=\frac{11}{6}\)
Vậy ta thấy ko tìm đc x,y,z tm.