Can anyone help me answer these two questions?

1. Find the coordinates of the point of intersection for the graphs

x^2=25-9y^2

xy=-4

I am slightly confused on how I would find x and y

The second question is graph each system of linear inequalities

x^2+4y less than 16

x^2 less than y^2+4

What I do not understand in this question is how I could get it to y=mx+b

Because whenever I move it I end up getting a negative?