Answer:
the amount of depreciation to be charged against the machine during each of the remaining years of its useful life is $2666.67
Step-by-step explanation:
Straight Line Depreciation Charges the same amount for depreciation on the PPE item.
Depreciation Expense = (Cost - Salvage Value) / Useful Life
Year 1 
Depreciation Expense = ($12,000 - $2,000) / 5
 = $ 2,000
Year 2 
Depreciation Expense = $ 2,000
Year 3 
Depreciation Expense = $ 2,000
Year 4
1. Adjust The Depreciable Amount
Depreciable Amount = Cost - Accumulated Depreciation to date - New Salvage Value
 = $12,000 - $ 2,000 - $ 2,000
 = $ 8,000
2. Adjust the Remaining Useful Life staring Beginning of Year 4
Remaining Useful Life before adjustments is 2
Addition to 6 years is 1
Total useful life Remaining is 3
Depreciation Expense = Revised Depreciable Amount / Remaining Useful Life
 = $ 8,000 /3
 = $2666.67