Solve the System by Substitution $$\begin{array} { r } x + 7 y = 27 \\6 x + 7 y = 57\end{array}$$

Multiple Choice

Solve the system by substitution.
- $$\begin{array} { r } x + 7 y = 27 \\6 x + 7 y = 57\end{array}$$

A) $\{ ( 7,2 ) \}$
B) $\{ ( 6,3 ) \}$
C) $\varnothing$
D) $\{ ( - 3,6 ) \}$