On 01/01/xX1, a company purchased equipment for $61,000. The company estimates a 7 year useful life and a $5,000 residual value. The depreciation method used is sum-of-the-years'-digits. What is the depreciation base of the equipment? (Do not include any words or signs in your answer; enter number only. If zero, enter "O") What is the book value of the equipment on 12/31/X4? (Enter your answer rounded to the nearest whole dollar, as applicable. Do not include any words or signs in your answer; enter number only) $