Solve the System of Equations by the Substitution Method $$\begin{aligned}x + y & = - 9 \\y & = - 4 x\end{aligned}$$

Multiple Choice

Solve the system of equations by the substitution method.
- $$\begin{aligned}x + y & = - 9 \\y & = - 4 x\end{aligned}$$

A) $\{ ( 3 , - 12 ) \}$
B) $\{ ( 3,12 ) \}$
C) $\{ ( - 3 , - 12 ) \}$
D) $\{ ( - 3,12 ) \}$