A computer system, which has s useful life of 5 years, costs $10,000. Its estimated salvage value is $778, use the double-declining-depreciation method to compute the annual depreciation allowances and the resulting book values. 3. Cost of an automobile is $10,000, it has a useful life of 5 years, and a salvage value of $2,000. Use the straight-line depreciation method to compute the annual depreciation allowances and the resulting book values