\[\left\{ \begin{matrix} 6z - 5x = 2\ \ \ \ | \cdot ( - 2) \\ 4z - 2x = 10\ \ \ \ \ \ | \cdot 5\ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} - 12z + 10x = 4\ \ (1) \\ 20z - 10x = 50\ \ \ (2) \\ \end{matrix} \right.\ \]
\[(1) + (2) \Longrightarrow 8z = 46\]
\[\left\{ \begin{matrix} 8z = 46\ \ \ \ \ \ \ \ \ \\ 4z - 2z = 10 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} 8z = 46\ \ \ \ \ \ \ \ \ \ \ \\ 2x = 4z - 10 \\ \end{matrix} \right.\ \]