1. On January 1, 2018, B Coorp. purchases a machine for $12,000. The machine has a $2,000 salvage value and an estimated 5-year useful life. On March 1, 2021, B Corp. changes the estimated usefulness life to 7 years (additional 2 years). B Corp records depreciation expense at the end of each year. How should B Corp calculate depreciation.

a. Update 2018, 2019, and 2020 financial statements assuming a 7-year useful life to begin with b. Update the depreciation calculation starting in 2021.