Find the average rate of change of the function over the given intervals.
f(x) = 12x³ + 12 a) [4,6], b) [1,1]
a) The average rate of change of the function f(x) = 12x³ + 12 over the interval [4,6] is ____
b) The average rate of change of the function f(x) = 12x³ + 12 over the interval [1,1] is ______