Porter Inc. acquired a machine that cost $378,000 on October 1, 2019. The machine is expected to have a four-year useful life and an estimated salvage value of $39,000 at the end of its life. Porter uses the calendar year for financial reporting. Depreciation expense for one-fourth of a year was recorded in 2019. b. Using the double-declining-balance depreciation method, calculate the depreciation expense for the year ended December 31, 2021, and the net book value of the machine at that date. (Round intermediate calculations.) Answer is complete but not entirely correct. $ Depreciation expense Net book value 82,688 82,688 $