Hello, Looking for guidance on how to solve these types of problems for my most recent math lab.

Any assistance is greatly appreciated!

Suppose that c(x) = 4x - 40x- + 16,000x is the cost of manufacturing x items. Find a production level that will minimize the average cost of making x items. The production level that minimizes the average cost of making x items is x = (Simplify your answer.) At this level, the average cost of making x items is $ (Simplify your answer.)