Poling Construction Corporation, the premier builder in southern West Virginia, purchased equipment for a new road project spanning from Beckley to Oceana. The equipment cost the company $$850,000.$ The estimated salvage at the end of the expected life of $5$ years is $$80,000.$ The company uses a straightline depreciation method to estimate their tax burden and needs your help. Find the book value of the equipment after three years of service.