Solve the System by the Substitution or Elimination Method $$\left( \begin{array} { r l } 2 x ^ { 2 } + y ^ { 2 } & = 15 \\x ^ { 2 } - y ^ { 2 } & = 6\end{array} \right)$$

Multiple Choice

Solve the system by the substitution or elimination method. $$\left( \begin{array} { r l } 2 x ^ { 2 } + y ^ { 2 } & = 15 \\x ^ { 2 } - y ^ { 2 } & = 6\end{array} \right)$$

A) $( \sqrt { 7 } , 1 ) , ( \sqrt { 7 } , - 1 ) , ( - \sqrt { 7 } , 1 ) , ( - \sqrt { 7 } , - 1 )$
B) $( \sqrt { 7 } , 1 ) , ( \sqrt { 7 } , - 1 )$
C) $( \sqrt { 8 } , 1 ) , ( \sqrt { 8 } , - 1 ) , ( - \sqrt { 8 } , 1 ) , ( - \sqrt { 8 } , - 1 )$
D) $( - \sqrt { 8 } , 1 ) , ( - \sqrt { 8 } , - 1 )$
E) $( - \sqrt { 7 } , 1 ) , ( - \sqrt { 7 } , - 1 )$