Beaver Construction purchases new equipment for $50,400 cash on April 1, 2021. At the time of purchase, the equipment is expected to be used in operations for seven years (84 months) and have no resale or scrap value at the end. Beaver depreciates equipment evenly over the 84 months ($600/month). 

(1) Record the purchase of equipment on April 1. 

(2) Record the adjusting entry for depreciation on December 31, 2021. 

(3) Calculate the year-end adjusted balances of Accumulated Depreciation and Depreciation Expense (assuming the balance of Accumulated Depreciation at the beginning of 2021 is $0).