The function that describes your driving at a pace of 65 miles per hour can be considered constant. This is because your speed (65 miles per hour) does not change over time; it remains constant as you drive toward your destination.
If we were to represent distance as a function of time, it would be a linear function, specifically \( d(t) = 65t \), where \( d \) is distance and \( t \) is time in hours. However, since the question specifically asks about your speed, it is appropriate to describe it as a constant speed.