Solve the System by the Substitution Method $$\begin{array} { l } x y = 56 \\x + y = - 15\end{array}$$

Multiple Choice

Solve the system by the substitution method.
- $$\begin{array} { l } x y = 56 \\x + y = - 15\end{array}$$

A) $\{ ( - 7 , - 8 ) , ( - 8 , - 7 ) \}$
B) $\{ ( 7 , - 8 ) , ( 8 , - 7 ) \}$
C) $\{ ( - 7,8 ) , ( - 8,7 ) \}$
D) $\{ ( 7,8 ) , ( 8,7 ) \}$