The following are independent errors: a. In January 2016, repair costs of $9,960 were debited to the Machinery account. At the beginning of 2016, the book value of the machinery was $96,600. No residual value is expected, the remaining estimated life is 10 years, and straight-line depreciation is used. b. All purchases of materials for construction contracts still in progress have been immediately expensed. It is discovered that the use of these materials was $10,250 during 2015 and $11,940 during 2016. c. Depreciation on manufacturing equipment has been excluded from manufacturing costs and treated as a period expense. During 2016, $43,200 of depreciation was accounted for in that manner. Production was 17,500 units during 2016, of which 4,200 remained in inventory at the end of the year. Assume there was no inventory at the beginning of 2016. Required: Prepare journal entries for the preceding errors discovered during 2017. Ignore income taxes.