Unit rate of. 15 degrees. in 2 hours

Ok, so we need to find the unit rate of 15 degrees in 2 hours.
this is a very simple question, it says here that in 2 hours, there are 15 degrees.
Thus we  need to find the unit rate of this given situation per hours.
=> hour many hours are there?  The answer is 2
so let us divide 2 by 15 to get the unit rate of the given situation
=> 15 degrees / 2 hours
=> 7.5 degrees / hours
Thus, the unit rate of 15 degrees per 2 hours is 7.5 degrees per hour.

It’s going to be d. 4x^2-4x-19’