I don't understand why this problem is incomplete. Does each account need two additional credit/debit entries to reverse the mistake?

Problem 4-96 The following errors in recording the transactions for December were discovered in the general journal the next month after the data had been posted to the ledger Dec. 5 Discovered that a purchase of office equipment for $1,300 cash was recorded as a debit to Shop Equipment and a credit to Cash. 10 Discovered that a check for $3,100 to the owner, Hank Rudolph, to pay one month's utilities on his personal apartment was recorded as a debit to Utilities Expense and a credit to Cash. 15 Discovered that a receipt of $31,500 cash from a customer for services performed was recorded as a debit to Cash and a credit to Accounts Receivable. 20 Discovered that $3,450 for this month's rent was recorded as a debit to Cash and a credit to Prepaid Rent. Record the necessary correcting entries