Answer: The asset's cost minus its accumulated depreciation.
Explanation: The book value of equipment owned by a company is the total worth of a company if it liquidated all its assets and substracted it's liabilities.
For easy computation it can be described as the Value of the Assets minute the accumulated depreciation for an equipment that depreciates according to time. Book value is of importance to the business as it helps to show what amount is actually the worth of a company when liquidated.
