Solve Linear Systems by Substitution
- $$\begin{array} { c } x + 8 y = - 49 \\- 4 x + 7 y = - 77\end{array}$$

Solve Linear Systems by Substitution
- $$\begin{array} { c } x + 8 y = - 49 \\- 4 x + 7 y = - 77\end{array}$$

A) $\{ ( 7 , - 7 ) \}$
B) $\{ ( 6 , - 6 ) \}$
C) $\{ ( - 7 , - 6 ) \}$
D) $\varnothing$