Journal entries for revising estimate of life. Give the journal entries for the following selected transactions of Fort Manufacturing Corporation. The company uses the straight-line method of calculating depreciation and closes its books annually on December 31 .

a. The firm purchases a polishing machine on November 1 , Year 9 , for $\$ 45,000$. It estimates that the machine will have a useful life of 12 years and a salvage value of $\$ 1,800$ at the end of that time. Give the journal entry for the depreciation at December 31, Year 9 .

b. Record the depreciation for the year ending December 31, Year 10.

c. In August, Year 15, the firm estimates that the machine will probably have a total useful life of 14 years and a $\$ 960$ salvage value. Record the depreciation for the year ending December 31, Year 15.

d. The firm sells the machine for $\$ 10,000$ on March 31, Year 20. Record the entries of that date, assuming that the firm records depreciation as indicated in part $\mathbf{c}$.