3. Use straight-line depreciation to calculate the annual depreciation for equipment that cost 10,000 with a residual value of 2,000 and a useful life of four years (5 points). 4. Use units-of-activity depreciation to calculate the annual depreciation for equipment that cost 20,000 with a residual value 5,000 and is expected to run for 15,000 hours. The machine ran 6,000 hours this year (5 points). 5. Use double-declining balance to calculate the first year of depreciation on a machine that cost 70,000 with a residual value of 20,000 and a useful life of 10 years (5 points). 6. Calculate interest expense for a 100,000, 9%, 60-day note (5 points). 7. Calculate net pay when gross pay was $ 4,000, social security was $ 240, Medicare was $ 50, Federal Income tax was $ 1,200, and the retirement deduction was $ 300 (5 points)