Equipment with a cost of $559,400 has an estimated residual value of $55,400, has an estimated useful ufe of 40 years, and is depreciated by the straight-line mechod. a. Determine the amount of the annual depreciation. b. Determine the book value after 17 full years of use. c. Assuming that at the start of the year 18 the remaining life is estimated to be 30 years and the residual value is estimated to be $48,200, determine the depreciabian expense for each of the remaining 30 years