Solve the System of Equations by the Substitution Method $$\left\{ \begin{array} { r } x + y = 6 \\y = 2 x\end{array} \right.$$

Multiple Choice

Solve the system of equations by the substitution method.
- $$\left\{ \begin{array} { r } x + y = 6 \\y = 2 x\end{array} \right.$$

A) $( 2 , - 4 )$
B) $( - 2,4 )$
C) $( - 2 , - 4 )$
D) $( 2,4 )$