Use Cramer S Rule to Solve the System of Equations $\left\{ \begin{array} { l } x + y + 2 z = 12 \\x + 2 y + z = 11 \\2 x + y + z = 9\end{array} \right.$

Essay

Use Cramer s rule to solve the system of equations, if possible. If the equations of the system are dependent, or if the system is inconsistent, so indicate. $\left\{ \begin{array} { l } x + y + 2 z = 12 \\x + 2 y + z = 11 \\2 x + y + z = 9\end{array} \right.$