Perdue Company purchased equipment on April 1 for $56,700. The equipment was expected to have a useful life of 3 years, or 6,480 operating hours, and a residual value of $1,620. The equipment was used for 1,200 hours during Year 1,2,300 hours in Year 2,1,900 hours in Year 3 , and 1,080 hours in Year 4 . Required: Determine the amount of depreciation expense for the years ended December 31, Year 1, Year 2, Year 3, and Year 4, by (a) the straight-line micthod, (b) the units-of-activity method, and (c) the double-declining-balance method. Note: FOR DECLINING BALANCE ONLY, round the final multiplier to four decimal places. Then, round the answer for each year to the nearest whole dollar. a. Stroight-line method b. Units-of-activity method c. Double-declining balance method