lansbury company purchases equipment on january 1, year 1, at a cost of $469,000. the asset is expected to have a service life of 12 years and a salvage value of $40,000. a) compute the amount of depreciation for each of years 1 through 3 using the straight-line depreciation method. b) compute the amount of depreciation for each of years 1 through 3 using the sum-of-the-years'-digits method. c) compute the amount of depreciation for each of years 1 through 3 using the double-declining balance method.