a. Stone Co. acquired a machine on January 1, 2022, at a cost of $44,800. The machine has an estimated salvage value of $5,600 at the end of its 7 -ycar useful life. The depreciation adinetment is done at the end of everv oalandar unar b. Rock Co. acquired a equipment on June 1, 2022, at a cost of $44,800. The machine has an estimated salvage value of $5,600 at the end of its 7 -year useful life. The depreciation