What is the average rate of change of y=4x^3 over the interval P(1, 4) and Q(5, 500)?

How much did it change?

YQ = 4(500)^3
YP = 4 (1)^3

difference = 4 (125*10^6)
length of interval = 5 - 1 = 4
so
4 (125*10^6)/4
= 125 *10^6