4. (3 points) Machinery purchased for $150,000 by Tom Brady Co. in 2010 was originally estimated to have a life of 12 years with a salvage value of $24,000 at the end of that time. Depreciation has been recorded for 7 years on this basis. In 2017, it is determined that the total estimated life should be 14 years with a salvage value of $20,000 at the end of that time. Assume straight-line depreciation. Instructions (a) Determine the depreciation expense for 2017.