Suppose that f(t) = t~ + 4t -5 (a) What is the average rate of change of f(t) over the interval 3 to 4? (b) What is the (instantaneous) rate of change of f(t) when t = 3? The average rate of change of f(t) over the interval 3 to 4 is (Simplify your answer.) The (instantaneous) rate of change of f(t) when t = 3 is (Simplify your answer.)