Equipment is purchased on July 1, 2011 for $250,000. The estimated salvage value and useful life are $25,000 and 5 years, respectively. What is the depreciation expense for 2012 under: (1) straight-line method, (2) sum-of-years-digits method, and (3) double-declining balance method

The answer is S-L: 45,000 DDB: 80,000SYD:67,500

Can you please explain step by step solution.