Albatross Company purchased a piece of machinery for $60,000 on January 1, 2019, and has been depreciating the machine using the double-declining-balance method based on a five-year estimated useful life and no salvage value. On January 1, 2021, Albatross decided to switch to the straight-line method of depreciation. The salvage value is still zero and the estimated useful life did not change. Ignore income taxes. Required:
a. What type of accounting change is this, and how should it be handled?
b. Prepare the journal entry to record depreciation for 2017. Show all calculations clearly.