Answer
$$\left( {3,5} \right)$$
Work Step by Step
$$\eqalign{
& \,\,\,\,x + y = 7\,\,\,\,\,\,\,\left( {\bf{1}} \right) \cr
& {x^2} + {y^2} = 25\,\,\,\,\left( {\bf{2}} \right) \cr
& \cr
& {\text{We know the point }}\left( {3,y} \right),{\text{ then }}x = 3 \cr
& {\text{Substitute }}x = 3{\text{ into the equation }}\left( {\bf{1}} \right){\text{ and solve for }}y \cr
& \,2 + y = 7 \cr
& \,\,\,\,\,\,\,\,\,y = 5 \cr
& \cr
& {\text{Therefore, one of the solutions onf the nonlinear systems is }} \cr
& \left( {3,5} \right) \cr} $$
