Independent variable: the number of days. Time is (almost always) independent.
Dependent: the length of your hair. It is based on how many days it has been since your last haircut.
Description: I am not really sure what you are looking for here, but I'll take a guess. As the number of days increases since your last haircut, the length of your hair will get longer. This would be a positive slope linear equation in quadrant I. The y intercept would be the length of your hair at Days = 0 (meaning the day you got your hair cut).