George, opened a dental practice on January 1, 2022. During the first month of operations, the following transactions occurred.

1. Performed services for patients who had dental plan insurance. At January 31, $750 of such services were performed but not yet billed to the insurance companies.

2. Utility expenses incurred but not paid prior to January 31 totaled $520.

3. Purchased dental equipment on January 1 for $80,000, paying $20,000 in cash and signing a $60,000, 3-year note payable. The equipment depreciates $400 per month. Interest is $500 per month.

4. Purchased a 1-year malpractice insurance policy on January 1 for $15,000.

5. Purchased $1,600 of dental supplies. On January 31, determined that $400 of supplies were on hand.

Required: Prepare the adjusting entries on January 31.