Not sure where to start. I'm on 63a.. I think I'm supposed to solve f(x,y) = x+y and x^2+y^2 = 4 for y giving me y = -x and y = sqrt(4-x^2) and then graph those two but I'm not sure what to do next.

I could be completely wrong also.

https://imgur.com/a/lzrShWV