The range is virtually the answer to the question,
"In which interval can find all y-values of the function".
So you look at the y-axis and see that your function begins with
(including -5 because of the dot on the graph) and ends at including
.
So the interval notation is,
![y\in[-5,-1]](https://tex.z-dn.net/?f=y%5Cin%5B-5%2C-1%5D)
But you are asked to specify the set notation of the interval, to do so first rewrite the interval using inequality operators, say we find some y in between (and including) -5 and -1,

To specify that this is a set use curly bracelets and a bar,
.
The y before bar is a step function and everything followed after the vertical bar is the range of the step function.
Hope this helps.