I’m not entirely sure why, but it works when surrounded by " " instead of :
I’m assuming it has something to do with the [-) combination instead of matching (). However, keep in mind that if a student enters an extra space, it will return a false incorrect, so you may want to set up an “or” statement to allow -1, infinity or other combinations.
In general, it’s not best practice to match Latex, but I’m not sure if there is another way to check interval notation in a math input.