\(\left\{{}\begin{matrix}4x-3z=z\\6y-x=z\\2x+3y+4z=19\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=z\\6y-x=z\\2x+3y+4z=19\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=z\\3y=z=x\\3x+3y+4z=19\end{matrix}\right.\)
\(\Leftrightarrow2x+x+4x=19\)
\(\Leftrightarrow x=z=\dfrac{19}{7}\)
\(\Leftrightarrow y=\dfrac{19}{7}:3=\dfrac{19}{21}\)
Vậy \(x=\dfrac{19}{7}\) , \(y=\dfrac{19}{21}\), \(z=\dfrac{19}{7}\) .