Final answer:
The depreciation expense for the equipment in 2017 under the double-declining balance method is $8,000.
Step-by-step explanation:
The depreciation expense for the equipment in 2017 can be calculated using the double-declining balance method. This method applies a constant rate to the book value of the asset each year.
The formula to calculate the depreciation expense is: Depreciation Expense = (1/Useful Life) x 2 x Book Value.
In this case, the useful life is 5 years and the book value in the first year is $20,000 (cost - residual value).
Substituting the values into the formula, we get: Depreciation Expense = (1/5) x 2 x $20,000 = $8,000.