XYZ Company purchased a machine for $50,000 on January 1, 2022. The machine has an estimated useful life of 10 years and a salvage value of $5,000. The company uses the straight-line method to depreciate the machine. What is the depreciation expense and the book value of the machine at the end of the fifth year? On January 1, 2025, the company decides to change the depreciation method from straight-line to double-declining-balance method. What is the depreciation expense and the book value of the machine at the end of the eighth year using the double-declining-balance method? Show all the necessary calculations.