Solve the System of Linear Equations $\left\{ \begin{array} { r } x + z = 2 \\y + 2 z = 7 \\- x + z = 4\end{array} \right.$

Solve the system of linear equations. $\left\{ \begin{array} { r } x + z = 2 \\y + 2 z = 7 \\- x + z = 4\end{array} \right.$