The yield, Y, of an apple orchard (measured in bushels of apples per acre) is a function of the amount, x, of fertilizer in pounds used per acre. Suppose Y= 320 + 140-10x2 a. What is the yield if S pounds of fertilizer is used per acre? b. Find Y5) and interpret (write a meaningful sentence) what it means. c. Given your answer to part b, should more or less fertilizer be used?