On January 1, 20X2, Walsh Corp. (WC) purchased equipment costing $600,000. At that time, it estimated the equipment would have a useful life of seven years and a residual value of $40,000, and depreciated the equipment on a straight-line basis. Subsequent to WC making all preliminary adjusting journal entries for 20X5 based on this estimate, management received new facts with respect to the longevity of the equipment. Considering this information, WC now believes the remaining useful life of the equipment is six years (from the beginning of 20X5), and that the estimated residual value at the end of the equipment’s useful life will be $0. The company is subject to an income tax rate of 30%.

Required:
a) Identify the type of accounting change and the required accounting treatment.
b) Prepare the journal entries necessary to record the adjustment to the equipment’s estimated useful life on December 31, 20X5.