Company ABC purchased a new machine for $60,000 on January 1, 2023. The machine has an expected useful life of 10 years and a residual value of $6,000. The company uses the straight-line method for depreciation. On December 31, 2025, the company decides to change its depreciation method to double-declining balance for this machine.

a) Calculate the annual depreciation expense under the straight-line method for the years 2023-2025.
b) Calculate the book value of the machine as of December 31, 2025, under the straight-line method.
c) Calculate the accumulated depreciation as of December 31, 2025, under the straight-line method.
d) Calculate the annual depreciation expense under the double-declining balance method for the years 2023-2025.
e) Calculate the book value of the machine as of December 31, 2025, under the double-declining balance method.
f) Calculate the accumulated depreciation as of December 31, 2025, under the double-declining balance method.