i dont if i did it right can you give me an explanation for the question

On January 1, 2020, Air Continental purchased a used Bombardier aircraft at a cost of $65,000,000. Air Continental expects the plane to remain useful for four years (5,250,000 miles) and to have a residual value of $4,000,000. Air Continental expects the plane to be flown 875,000 miles the first year and 675,000 miles the second year. (Note: "Miles" is the unit of measure used in the airline industry) Compute second-year amortization on the plane using the following methods: a. Straight line b. UOP c. DDB ... Calculate the second-year amortization: a. Using the straight-line method, amortization is $15250000. (Round your answer to the nearest whole dollar.) b. Using the units-of-production method, amortization is $78428572. (Do not round intermediary calculations. Only round the amount you input in the cell to the nearest dollar.) c. Using the double-declining-balance method, amortization is $(Do not round intermediary calculations. Only round the amount you input in the cell to the nearest dollar.)