For which interval is the function constant?
It would be nice if you tried to teach this person, or anyone who comes along later and wants learn from it.
Maybe if you had explained what constant meant, and not given the answer at all, that would have been a much better answer.
(But I will give you a point for your interest and for having to listen to me. ;)
Sorry!!! I was in a rush because I was in a Spanish Test and had to finish it by 3 (had to go to work). I just wanted to answer before I left and didn't have time to explain.
It is constant because it doesn't increase or decrease and just continues to go in a straight line. I hope that makes sense. I'm not the best at explaining.