answer: X = 3,718 units per year, please do step by step!

56. Your company is considering the introduction of a new product line. The initial investment required for this project is $500,000, and annual maintenance costs are anticipated to be $35,000. Annual operating cost will be in direct proportion to the level of production at $8.50 per unit, and each unit of product can be sold for $50.00. If the project has a life of 7 years, what is the minimum annual production level for which this project is economically viable? Work this problem on an after-tax basis, Assume 5-year SL depreciation (SVs=0), MV7 =0, an effective income tax rate of 40%, and an after-tax MARR of 10% per year