The domain is the first set of the ordered pair. When finding the domain you are supposed to find which x value it starts from to where it ends. The x value starts from 0 and ends and the 9th unit on the x-axis which would give us 0,9 now since both points are closed you would use these symbols [ ] to show that it is closed meaning the answer would be [0,9]
Note:
I'm sorry if this is wrong but this is what I believe the answer is.
