Before write off:

Net realizable value of the accounts receivable = $320,000 - $14,000

= $306,000

After write off - account receivable from Burton Company of $1,210:

This entry has dual impact- Account receivable will decreased as well at same time writoff will be adjusted from allowance for doubtful accounts.

Net realizable value of the accounts receivable = ($320,000 - $1,210) - ($14,000 - $1,210)

= $318,790 - $12,790

=$306,000

Thus accounts receivable before and after the write-off were $306,000.