Revision of Depreciation Equipment with a cost of $577,400 has an estimated residual value of $66,400, has an estimated useful life of 35 years, and is depreciated by the straight-line method. a. Determine the amount of the annual depreciation. $ 14,600 b. Determine the book value after 17 full years of use. X c. Assuming that at the start of the year 18 the remaining life is estimated to be 24 years and the residual value is estimated to be $70,000, determine the depreciation expense for each of the remaining 24 years. $ Feedback Check My Work Asset minus residual value equals depreciable cost. Straight-line method allocates the depreciable cost of the asset equally over the expected useful life. The book value is the fixed asset cost less accumulated depreciation. Revising depreciation is necessary when estimates of residual values and/or useful lives of fixed assets change due to abnormal wear and tear or obsolescence