Skysong SE purchased machinery on January 1,2022, for 72,000. The machinery is estimated to have a residual value of 7,200 after a useful life of 8 years. (a). (b) Compute 2022 depreciation expense using the sum-of-the-years'-digits method, assuming the machinery was purchased on April 1, 2022. (Round answer to 0 decimal places, e.g. 5,125.) Depreciation expense