Sheffield Corporation purchased a new machine for its assembly process on August 1, 2017. The cost of this machine was $122,616. The company estimated that the machine would have a salvage value of $13,416 at the end of its service life. Its life is estimated at 5 years, and its working hours are estimated at 19,500 hours. Year-end is December 31. Compute the depreciation expense under the following methods. Each of the following should be considered unrelated. (Round depreciation rate per hour to 2 decimal places, e.g. 5.35 for computational purposes. Round your answers to o decimal places, e.g. 45,892.) (a) Straight-line depreciation for 2017 (b) Activity method for 2017, assuming that machine usage was 880 hours (c) Sum-of-the-years'-digits for 2018 (d) Double-declining-balance for 2018