on january 1, 2024, canseco plumbing fixtures purchased equipment for $54,000. residual value at the end of an estimated four-year service life is expected to be $10,000. the company expects the equipment to operate for 20,000 hours. the equipment operated for 3,400 and 4,200 hours in 2024 and 2025, respectively. required: calculate depreciation expense for 2024 and 2025 using straight-line method. calculate depreciation expense for 2024 and 2025 using double-declining-balance method. calculate depreciation expense for 2024 and 2025 using units-of-production using hours operated