Given data shows that $1000 as salvage value and purchased computer for $8000
Depreciation was:
(8,000 - 1,000) / 5 = 1,400 per year.
Two year's depreciation = 2,800
Book value after two years = 8,000 - 2,800 = 5,200
After the estimates are revised, there are two more years remaining with a salvage value of 500.
(5,200 - 500) / 2 = 2,350 depreciation for 2018