Solve the System of Equations $$\begin{array} { l } x - y + z = - 7 \\x + y + z = 1 \\x + y - z = 9\end{array}$$

Multiple Choice

Solve the system of equations.
- $$\begin{array} { l } x - y + z = - 7 \\x + y + z = 1 \\x + y - z = 9\end{array}$$

A) $\{ ( 1 , - 4,4 ) \}$
B) $\{ ( 4 , - 4,1 ) \}$
C) $\{ ( - 4,1,4 ) \}$
D) $\{ ( 1,4 , - 4 ) \}$