Prepare journal entries to record these transactions:
Mar. 21 Accepted a $6,200, six-month, 4% note dated today from Bradley Brooks in granting a time extension on his past-due account.
Sept. 21 Brooks dishonoured his note when presented for payment.
Dec. 31 After exhausting all legal means of collection, wrote off Brooks's account against the Allowance for Doubtful Accounts.