Answer:
Jan 1, 2021 DR Patent $237,000
CR Cash $237,000
Dec 31, 2021 DR Amortization Expense $39,500
CR Patent $39,500
Working
Amortization Expense = 237,000/ 6 years useful life = $39,500
Dec 31, 2022 DR Amortization Expense $39,500
CR Patent $39,500
Jan 31, 2023 DR Patent $57,000
CR Cash $57,000
Dec 31, 2023 DR Amortization Expense $53,750
CR Patent $53,750
Working
New Patent Value = (237,000 - 39,500 + 39,500 + 37,000)
= $215,000
Amortization expense = 215,000/ 4 remaining years = $53,750