Concord Automotive purchased equipment on October 1, 2024, at a total cost of $180,000. The machine has an estimated useful life of 8 years or 100,000 hours, and an estimated residual value of $40,000. During 2024 and 2025, the machinery was used 6,200 and 14,600 hours, respectively. Compute depreciation expense at December 31, 2024 and December 31, 2025, under the following depreciation methods: 2024 2025 Straight-line depreciation $ $ Units-of-production depreciation $ $ Double diminishing-balance depreciation $ $