A three-year-old machine has a cost of $83,000, an estimated residual value of $3,000, and an estimated useful life of five years. The company uses straight-line depreciation. Calculate the net book value at the end of the third year. A three-year-old machine has a cost of $83,000, an estimated residual value of $3,000, and an estimated useful life of five years. The company uses straight-line depreciation. Calculate the net book value at the end of the third year