Please show all equations and work used when using Excel.

The gas drilling company, North Eastern Star, (which makes decisions based on a discount rate of 10%, is considering the purchase of a natural gas powered turbine generator to replace its aging fleet of diesel generators for producing power at job sites. The gas turbine generator will cost $85,000. Through fuel savings, the generator will result in a net income of $18,000 annually. The generator will have a design life of 12 years. Using 10-ycar straight line and 10-year MACRS depreciation schedules, graph and compare the NPV payback periods for the generator under both depreciation scenarios assuming a flat income tax rate of 35%