I am struggling to understand the end of problem C and all of problem D

Take me to the text Equipment was purchased on January 1, 2015 for $70,000. The asset is expected to last for four years, at which time the estimated residual value will be $12,000. Required ) Prepare a table showing the amount of depreciation expense each year, accumulated depreciation to date and net book value. The company uses straight-line depreciation. Do not enter dollar signs or commas in the input boxes. Round all dollar figure answers to the nearest whole number Year Cost of Long-Term Asset Depreciation Expense Accumulated Depreciation Net Book Value 2015 $70,000 $ 14500 v 14500 $ 55500 016 $70,000 $14500 29000 $ 4 2017 $70,000 $ 14500 $ 43500 $ 26500 2018 $70,000 $ 14500 $ 5800 $ 12000 b) The asset was sold for $14,000 on the first day of 2019. Prepare the journal entry to record the sale. Enter all debit accounts in alphabetical order. Enter all credit accounts in alphabetical order. Date Account Title and Explanation Debit Credit Jan Accumulated Depreciation 58000 Cash 14000 Equipment 70000 Gain on Disposal of Asset 2000 Sale of equipment for cash () Using the same purchase information at the beginning of the question, prepare the table assuming that the company used double-declining-balance depreciation. Year Net Book Value at the Beginning of the Year Depreciation Expense Accumulated Depreciation Net Book Value at the End of the Year 2015 $ 70000 $ 35000 $ 35000 $ 3500 2016 $35000 $ 17500 $ 52500 $ 17500 2017 17500 $5500 58000 12000 2018 $ 12000 $2000 $ 12000 x $ 12000 d) Using the same purchase information and residual value at the beginning of the question, assume that the company uses the units-of-production method. The asset can produce one million units. Prepare the depreciation table. Year Cost of Long-Term Asset Units Produced Depreciation Expense Accumulated Depreciation Net Book Value 2015 $70,000 190.000 2016 $70,000 230,000 2017 $70,000 140,000 2018 $70,000 220,000 Check