Answer and Explanation:
The adjusting entry is shown below:
Bad debt expense Dr $2,900 ($5,100 - $2,200)
To Allowance for doubtful accounts $2,900
(Being the bad debt expense is recorded)
Here it debited the bad debt expense as it increased the assets and the allowance for doubtful accounts is credited as it decreased the assets
Also the expense and assets contains normal debit balance