please help me wih these

1.Find the average value fave of the function f on the given interval.

f(x) = 18xx2,[0, 4]

2.Find the average value have of the function h on the given interval.

h(x) = 3 cos4 x sin x,[0, π]

3.Find the numbers
b such that the average value of

f(x) = 3 + 10x − 9x2

on the interval [0,
b] is equal to 4.