Which Method Should Be Used to Solve the System? Explain $$\begin{aligned}x ^ { 2 } + y ^ { 2 } & = 49 \\- 6 x - 4 y & = 7\end{aligned}$$

Essay

Which method should be used to solve the system? Explain your answer, including a description of the first step.
- $$\begin{aligned}x ^ { 2 } + y ^ { 2 } & = 49 \\- 6 x - 4 y & = 7\end{aligned}$$