Duval Industries purchased a laser-guided mitre saw on September 1, 2018 at a cost of $34,000. Depreciation for 2018 and 2019 was based on an estimated 8-year useful life and $8,000 estimated residual value. In 2020, Duval revised its estimates and now believes the laser mitre saw will have a total service life of an additional three years but the residual value will be only $2,000. Duval Industries uses the straight-line method (monthly basis) to depreciate all assets. Duval Industries has a December 31 year end. Instructions Calculate depreciation expense for 2018, 2019, and 2020