Answer:
Answer is given below.
Step-by-step explanation:
a Bad debts expense 8840 =10320-1480 
 Allowance for doubtful accounts 8840 
b Bad debts expense 11800 =10320+1480 
 Allowance for doubtful accounts 11800 
c Allowance for doubtful accounts 2130 
 Accounts receivable 2130 
d Bad debts expense 2130 
 Accounts receivable 2130