(Depreciation for Partial PeriodsSL, Act., SYD, and DDB) The cost of equipment purchased by Charleston, Inc., on June 1, 2010 is $89,000. It is estimated that the machine will have a $5,000 salvage value at the end of its service life. Its service life is estimated at 7 years; its total working hours are estimated at 42,000 and its total production is estimated at 525,000 units. During 2010 the machine was operated 6,000 hours and produced 55,000 units. During 2011 the machine was operated 5,500 hours and produced 48,000 units. Compute depreciation expense on the machine for the year ending December 31, 2010, and the year ending December 31, 2011, using the following methods. Straight-line 2010: 2011: Units-of-output 2010: 2011: Working hours 2010: 2011: Sum-of-the-years'-digits 2010: 2011: Declining balance (twice the straight-line rate) 2010: 2011