New production machinery has a first cost of $100,000. It's useful life is 10 years. It's estimated operating and maintenance costs are $10,000 and will increase by $3,000 each year. The before-tax market value will be $75,000 at the end of the first year then will decrease by $5,000 annually. This property is a 7 year MACRS property. The company uses a MARR of 9% and the marginal tax rate is 40%. Use excel with formulas to calculate the after tax cash flows and identify the minimum cost life and optimal life. excel must be used.