Use Matrices to Solve the System of Equations (If Possible) $$\left\{ \begin{array} { r l c } - x + y - z & = - 20 \\2 x - y + z & = 29 \\3 x + 2 y + z & = 29\end{array} \right.$$

Multiple Choice

Use matrices to solve the system of equations (if possible) .Use Gaussian elimination with back-substitution or Gauss-Jordan elimination.​ $$\left\{ \begin{array} { r l c } - x + y - z & = - 20 \\2 x - y + z & = 29 \\3 x + 2 y + z & = 29\end{array} \right.$$ ​

A) ​(-9,-3,8)
B) ​(-9,-3,-8)
C) (9,-3,8)
D) ​(9,-3,-8)
E) ​(9,3,8)