Question in one of my algebra I assignments

Question

I need to state the domain and range and whether or not the following relation is a function:

{(-3, -6), (-1, -6), (5, -6), (8, -6)}

All the answers and help will be very appreciated.

Answer 1

The domain is the union of the x-values which is {-3, -1, 5, 8}

The range is the union of the y-values which is {-6}

The relation is a function if every time you plug in a certain value of "x", you always get only one value for "y". In this case, there are no duplicate values of "x" to worry about so you can say it is a function.

IF there were a point included (besides those listed) of (-3, 17) then that would make one input of -3 give an output of -6 (the point (-3, -6)) while another input of -3 gave an output of 17 (the point (-3, 17)). That would make the relation NOT a function. To be a function, both inputs of -3 would need to have the same output (either -6 or 17)