I found that the unit cost of using production equip. is:
cost = 1.5x(2)[that is to the 2nd power] - 120x + 4,000
Because you wanted the number of units and the lowest cost from the graph, I gave you the answers by locating point on
the graph, which happens to be (40, 1600).
However, if you want to get this by ...
Solution is provided. Graph is provided.