a) {(x,y): x,y e Z, x + y = 0}

b) {(x,y): x,y e Z, xy = 0}

c) {(x,y): x,y e Z, x^2 + y^2 = 1}

For each of these, I have to answer:

1) is this a function with range Z?

2) If it is a function, what is its domain and image?

3) If its a function, is it 1-1? onto? a bijection?

4) If its a bijection, what is its inverse function?

x,y e Z means x and y can be any integer (pos or neg). Sorry for the notation.

Please Help! Thank you guys.