Question 288644
Hint: First solve for {{{y^2}}} in {{{4x^2 + y^2 - 64 = 0}}} to get {{{y^2=-4x^2+64}}}. Next replace the {{{y^2}}} term in the first equation with {{{-4x^2+64}}} (since the two are equal) to get {{{4x^2 - 56x + 9(-4x^2+64) + 160 = 0}}}.


From there, you have a quadratic equation (after simplification) in which you can use the quadratic formula to solve for 'x'. Once you have your solution(s) in terms of 'x', use the solution(s) to find the solution(s) in terms of 'y'.