Strong Metals Inc. purchased a new stamping machine at the beginning of the year at a cost of $580,000. The estimated residual value was $60,000. Assume that the estimated useful life was five years, and the estimated productive life of the machine was 260,000 units. Actual annual production was as follows: Year Units 173,000 2 62,000 3 30,000 4 53,000 5 42,000 a. Straight-line. Depreciation Accumulated Net Year Expense Depreciation Book Value At acquisition 2 4 b. Units-of-production. Depreciation Accumulated Net Year Expense Depreciation Book Value At acquisition 2 4 c. Double-declining-balance DepreciationAccumulated Net Year Expense Depreciation Book Value At acquisition 2 3 4