Give All Solutions of the Nonlinear System of Equations, Including $$\begin{array} { l } x ^ { 2 } + y ^ { 2 } = 85 \\x + y = - 13\end{array}$$

Multiple Choice

Give all solutions of the nonlinear system of equations, including those with nonreal complex components.
- $$\begin{array} { l } x ^ { 2 } + y ^ { 2 } = 85 \\x + y = - 13\end{array}$$

A) $\{ ( 6,7 ) , ( 7,6 ) \}$
B) $\{ ( - 6 , - 7 ) , ( - 7 , - 6 ) \}$
C) $\{ ( - 6,7 ) , ( - 7,6 ) \}$
D) $\{ ( 6 , - 7 ) , ( 7 , - 6 ) \}$