Write the Word or Phrase That Best Completes Each Statement $\begin{aligned}- 5 x ^ { 2 } + 3 y ^ { 2 } & = 49 \\x + 6 y & = 3\end{aligned}$

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.
- $\begin{aligned}- 5 x ^ { 2 } + 3 y ^ { 2 } & = 49 \\x + 6 y & = 3\end{aligned}$