Solve the System by the Substitution Method $$\left\{ \begin{array} { r } x + 7 y = - 2 \\3 x + y = 34\end{array} \right.$$

Multiple Choice

Solve the system by the substitution method.
- $$\left\{ \begin{array} { r } x + 7 y = - 2 \\3 x + y = 34\end{array} \right.$$

A) $\varnothing$
B) $\{ ( x , y ) \mid x + 7 y = - 2 \}$
C) $\{ ( 12 , - 2 ) \}$
D) $\{ ( - 2,3 ) \}$