Please demonstrate how to work the problem without using excel, Thank you

58. An investment of $450,000 is made in equipment that qualifies as 5-year equipment for MACRS-GDS depreciation. The then-current dollar before tax cash flows are given by a $50,000 increasing gradient series, with the cash flow the first year equaling $100,000. In addition, a $50,000 then-current sal- vage value occurs at the end of the 5-year planning horizon. A 40% tax rate and 4% inflation rate apply. The real ATMARR is 8%. a. Determine the after-tax cash flows, in constant dollars, for each year b. Determine the present worth for the investment. c. Determine the real internal rate of return for the investment