Describe the nature of the functions scale of economies

Question

You are given the following long run cost function:

TC = 160Q - 20Q² + 1.2Q³ Go from Q = 0 to Q = 12

1. Calculate the long run average cost and marginal cost. Plot these costs on a graph.

I need this set up in excel.

2. Describe the nature of this functions scale of economies. Over what range of output does economies of scale exist? Diseconomies of scale? Show this on the graph.