Find the Solution to the System of Equations by Substitution $$\begin{array} { l } x + y = - 6 \\x - y = 15\end{array}$$

Multiple Choice

Find the solution to the system of equations by substitution.
- $$\begin{array} { l } x + y = - 6 \\x - y = 15\end{array}$$

A) (4.5, -10.5)
B) (6, -10.5)
C) (4.5, 10.5)
D) (6, 4.5)