Use Matrices to Solve the System of Equations $\left\{ \begin{array} { r } 6 x + y - z = 1 \\x + 2 y + z = 5 \\5 y - z = 9\end{array} \right.$

Essay

Use matrices to solve the system of equations. If the equations of the system are dependent, or if the system is inconsistent, so indicate. $\left\{ \begin{array} { r } 6 x + y - z = 1 \\x + 2 y + z = 5 \\5 y - z = 9\end{array} \right.$