please explain. thank you!!!

22. The December 31, 2018 balance sheet of Heffernan Company had Accounts Receivable of $400,000 and a credit balance in Allowance for Doubtful Accounts of $32,000. During 2019, the following transactions occurred: sales on account, $1,500,000; sales returns and allowances, $50,000; collections from customers, $1,250,000; accounts written off, $36,000; previously written off accounts of $6,000 were collected. (a) Journalize the 2019 transactions listed above. (b) Prepare the journal entry to record bad debt expense for 2019 assuming that the company estimates that 7% of the ending balance in accounts receivable at December 31, 2019, will become uncollectible