Question 1205597
Domain = set of x coordinates = <font color=red>-5, -3, 7, 9</font>
Often we surround a collection of numbers in curly braces to denote a set. 
However, your teacher may or may not want these surrounding items. I would ask for clarification.


Range = set of y coordinates = <font color=red>-5, 5, 2, 7, 4</font>


Is it a function? <font color=red>No</font>. Why not? Because the input x = -3 leads to more than one output (y = 5 and y = 2). In other words, the x coordinate -3 repeats which is an indication we don't have a function. The output values can repeat but the function wouldn't be one-to-one (aka injective).


A function requires each input leads to exactly one and only one output.
One input ----> one output.
Visually you can use the vertical line test to check if it's a function or not.
</font>