1.) Hey guys, i need some help with a couple of questions.

1.) {(2,y): y is a subset of Z}. State the domain and range of each and state whether the relations are FUNCTIONS.

2.) Could someone please explain the meaning of {(x,y): y = 5 -x} more specifically what the (x,y) in the question denotes.

3.) State the largest possible domain and range for the function defined by the rule: y = sqrt(16-x^2). For this question i stated that the equation had to be greater than or equal to 0 but i got stuck when i got the solution, please help!