Description: Sal compares a rate given in an equation to a rate shown on a graph. Created by Sal Khan. Or you could say the unit rate of change of y with respect to x is 6.5 for every 1 change in x. In this graph right over here, as x changes 1, as x increases 1, y increases it looks like by about 3 and 1/2. So the unit rate of change here of y with respect to x is 3 and 1/2 for every unit increase in x.*Teacher Advisor is 100% free.