A hotdog vendor must pay a monthly fee to operate a food cart in the city park. The cost in dollars hotdogs in a month can be approximated by C(x) = 150 + 75x. Complete parts (a) through (d) below (a) Find the average-cost function. 150 + 75x The average-cost function is C(x) = X (b) Find and interpret the average cost at sales levels of 1000 hotdogs and 6000 hotdogs. The average cost at sales levels of 1000 hotdogs is $ 90 /100 hotdogs. (Round to the nearest cent as needed.) The average cost at sales levels of 6000 hotdogs is $ /100 hotdogs. (Round to the nearest cent as needed.)