Question

If f(4) = 7 and f '(x) ≥ 1 for 4 ≤ x ≤ 9, how small can f(9) possibly be?

Answer 1

Well if the slope is greater than or equal to 1 over that range then the smallest f(9) will be is when the slope is 1. So if we have a slope of one, then f(9) will be 12.