The definition of domain is the set of #x# values on the graph. The definition of the range is the set of #y# values on a graph.

So when you look at the domain you look at the #x#-axis (horizontal line). So where does the line stop and start on the #x#-axis? it goes on forever right? Because the side keeps expanding forever and ever so the domain would equal #oo# ... Now let's look at the range. The range is the set of y-values so if you have a paper on this tilt it so it's easier to see it looks like a big arrow, <. So the tip of this "arrow" touches -3 and then goes on forever and ever...

so you can either put y>-3 (y is bigger than negative 3) or,

#-3 < y < oo # (-3 is smaller than y but goes on forever).

Hope this was understandable please comment below if you have concerns...