E22.13 (LO 2) Excel (Change in Estimate-Depreciation) Peter M. Dell Co. purchased equip- ment for $510,000 which was estimated to have a useful life of 10 years with a salvage value of $10,000 at the end of that time. Depreciation has been entered for 7 years on a straight-line basis. In 2021, it is deter- mined that the total estimated life should be 15 years with a salvage value of $5,000 at the end of that time. Instructions a. Prepare the entry (if any) to correct the prior years' depreciation. b. Prepare the entry to record depreciation for 2021