Domain and range of the equation

Question

{(-5,6), (12,-1), (11,5), (11,2)}

Answer 1

The set of points provided is NOT a function because abscissa 11 yields 2 ordinates 5 and 2.

 

The domain of what might be called a "relation" is {-5, 12, 11} and the range  is {6, -1, 5, 2}.