A differentiable function f satisfies 1 ≤ f ′(x) ≤ 3 for all real numbers x .
Moreover, it is known that f (2) = 4 . Use the Mean Value Theorem to answer the following.
(a) What is the largest possible value of f(7) ? Explain.
(b) What is the smallest possible value of f(-4) ? Explain.