Write the Word or Phrase That Best Completes Each Statement $\begin{aligned}x ^ { 2 } + y ^ { 2 } & = 49 \\- 6 x - 4 y & = 7\end{aligned}$

Essay

Write the word or phrase that best completes each statement or answers the question.
Which method should be used to solve the system? Explain your answer, including a description of the first step.
- $\begin{aligned}x ^ { 2 } + y ^ { 2 } & = 49 \\- 6 x - 4 y & = 7\end{aligned}$