Excel please!

Your firm is contemplating the purchase of a new $500,000 computer-based order entry system. The system will be depreciated straight-line to zero over its five-year life. It will be worth $50,000 at the end of that time. You will save $150,000 before taxes per year in order processing costs, and you will be able to reduce net working capital by $70,000. If the tax rate is 30 percent, what is the IRR for this project? b) In the previous problem you used straight line depreciation. This time use the MACRS 3-year depreciation schedule and answer the question again. The project is still 5 years long)