Primarily, horizontal lines mean zero slope. Therefore the equation is y= 3 because you are only left with the y-intercept at this point. The rate of change is another way of saying slope. Function 2's slope is 5 and function 1's slope is 0. Therefore, the rate of change of function 2 is greater than the rate of change of function 1 by 5.
5 is the answer.
hope this helps :)
