Use Matrices to Solve the System of Equations $\left\{ \begin{array} { r } 6 x + y - z = 21 \\x + 2 y + z = 15 \\5 y - z = 23\end{array} \right.$

Multiple Choice

Use matrices to solve the system of equations. $\left\{ \begin{array} { r } 6 x + y - z = 21 \\x + 2 y + z = 15 \\5 y - z = 23\end{array} \right.$

A) $( 4,6,2 )$
B) $( 3,5,2 )$
C) $( - 3 , - 5 , - 2 )$
D) no solution
E) infinitely many solutions