Please explain your answer.

The cost of equipment purchased by Wildhorse, Inc., on June 1, 2020, is $132,300. It is estimated that the machine will have a $6,300 salvage value at the end of its service life. Its service life is estimated at 7 years, its total working hours are estimated at 63,000, and its total production is estimated at 787,500 units. During 2020, the machine was operated 7,140 hours and produced 65,450 units. During 2021, the machine was operated 6,545 hours and produced 57,100 units. Compute depreciation expense on the machine for the year ending December 31, 2020, and the year ending December 31, 2021, using the following methods. (Round depreciation per unit to 2 decimal places, e.g. 15.25 and final answers to O decimal places, e.g. 45,892.) 2020 2021 (a) Straight-line $ $ 10500 $ $ 18000 (b) Units-of-output $ $ 10472 $ $ 9136 (c) Working hours $ $ 14280 $ $ 13090 (d) Sum-of-the-years'-digits $ $ 13125 $ $ 15750 (e) Double-declining-balance (twice the straight-line rate) $ $ 27000 $ $