To find the range of a function what you have to take into account are all the values of y that the function takes.
We have then that in this case the values are:
from y = 3 (included)
up to y = -3 (not including it)
The range of the function is:
-3 <y <= 3
Answer:
the range of the function graphed below
-3 <y <= 3
