GENERAL JOURNAL PAGE 1 DEBIT CREDIT PR. DATE DESCRIPTION h Corporation purchased a new machine for its assembly process on September o, 2007. The cost of this machine was $317,900. The company estimated that the machine would have a salvage value of $28,900 at the end of its service life. Its life is estimated at 1 years and its working hours are estimated at 4,000 hours. Year-end is December 31. Instructions: Compute the depreciation expense under the following methods. (a) Straight-line depreciation. (b) Activity method (c) Sum-of-the-years'-digits (d) Double-declining balance