Answer:
bad debt expense 7,464 debit
       allowance for doubtful accounts   7,464 credit
--to record year-end adjustment for bad debt expense--
 allowance for doubtful accounts 3,171 debit
                    accounts receivables      3,171 credit
--to record write-off of a custoemr account--
Explanation:
We multiply each balance by their expected uncollectible amount:
Date   // Amount  // Expected    //  uncollectible
not due	127400	0.03         3,822
up to 30	90100	0.13                  11,713
up to 60	54500	0.19                 10,355
above 61  32700	0.33          10,791
                  Total        36,681
Allowance balance 29,217
Difference 36,681 - 29,217 = 7,464
The write-off will decrease both, account recievable and the allowance
Allowance for doubtful accounts
<u>Debit      Credit</u>
             36,681
3,171
Balance 33,510