Final answer:
To correct a misentry of $2,000 from Notes Payable to Accounts Payable after the books have closed, you need to debit Notes Payable and credit Accounts Payable for $2,000 in the next accounting period.
Step-by-step explanation:
When you discover that a $2,000 purchase was incorrectly credited to Notes Payable instead of Accounts Payable, and the books have already been closed, you would need to make an adjusting entry to correct this error. Since the books are closed, this entry would typically go into the next accounting period. The entry to correct the original mistake would debit Notes Payable for $2,000 and credit Accounts Payable for the same amount, thus moving the liability from one account to the other.