Answer:
Esquire Company
Date                            Particulars                  Debit           Credit
30 June                   Accounts  Receivable            $ 66,000
                                          Sales                $ 66,000
On June 30, 2021, the Esquire Company sold some merchandise to a customer for $66,000.
31 Mar                 Note Receivable         $ 66,000
                                   Account Receivable                  $ 66,000
Esquire agreed to accept a 8% note requiring the payment of interest and principal on March 31, 2022.
31 December   Notes Receivable                       $ 66,000
                                 Interest Receivable               $ 3960
                                             Sales                           $ 66,000
                              Interest Revenue                          $ 3960
To record the accrued interest earned. $66,000*8%= $ 5280. As it is for nine months the amount would be $ (5280/12)*9= $ 3960
31 March                   Cash                $ 71,280
                                               Interest Income $ 5280
                                                       Notes Receivable $ 66,000
March 31, 2022 collection of Note receivable and interest accrued.                    
2. The income will be understated by an amount of $ 3960 in 2021 if an adjusting entry is not made on Dec 31 of accrual interest.
The adjusting entry on 31st December 2022 of the interest accrual will not be required as interest has been received on March 31st 2022.
The income will be understated by $ 5280 in 2022 if an adjusting entry is not made on Mar 31st 2022 of the interest received.