The domain is the set of possible inputs and the range is the set of possible outputs. This is a function because each input goes to exactly one output.
========================================
Problem 2
This is a function as well. We do not have any input going to multiple outputs.
Domain = {-2, -3, 5}
Range = {6, 7, 8}
========================================
Problem 3
This is not a function. The input -4 goes to more than one output (outputs 3 and -1 at the same time)
You probably haven't learnt this but the general equations for circle with centre at the origin is x^2+y^2=R^2 where R is the radius of the circle so R^2=(1737+185)^2.I am lazy to press my calculator so type it in yourself.