Patco purchased a machine for $18,000 on January 2, 2021. It is expected to have a residual value of $2,000 and a useful life of 4 years. 1. Calculate the annual depreciation using straight line depreciation. 2. Prepare the journal entry to record the depreciation on December 31,2021. 3. Calculate the depreciation for 2021 and 2022 using the units of activity method. The useful life is 8,000 hours. It was used 2,100 hours in 2021 and 2,200 in 2022. 4. Calculate the depreciation for all 4 years using the declining balance method