Can you please give me the last answer for all of them, thank you.

Becker Office Service purchased a new computer system in 2016 for exist40,000. It is expected to have a five-year useful life and a exist5,000 salvage value. The company expects to use the system more extensively in the early years of its life. a. Calculate the depreciation expense for each of the five years, assuming the use of straight-line depreciation. b. Calculate the depreciation expense for each of the five years, assuming the use of double-declining-balance depreciation. d. Assume that Becker Office Service sold the computer system at the end of the fourth year for exist15,000. Compute the amount of gain or loss using each depreciation method