Please provide explanations for numbers 5 and 7. These are the ones that I am having trouble with and I have bolded them below. Thank you!

Pastina Company sells various types of pasta to grocery chains as private label brands. The company's reporting year-end is December 31. The unadjusted trial balance as of December 31, 2021, appears below.

Account Title	Debits	Credits
Cash	37,600
Accounts receivable	44,000
Supplies	3,500
Inventory	64,000
Notes receivable	24,000
Interest receivable	0
Prepaid rent	2,400
Prepaid insurance	8,000
Office equipment	96,000
Accumulated depreciation		36,000
Accounts payable		35,000
Salaries payable		0
Notes payable		54,000
Interest payable		0
Deferred sales revenue		4,000
Common stock		86,000
Retained earnings		38,500
Dividends	8,000
Sales revenue		166,000
Interest revenue		0
Cost of goods sold	90,000
Salaries expense	20,900
Rent expense	13,000
Depreciation expense	0
Interest expense	0
Supplies expense	3,100
Insurance expense	0
Advertising expense	5,000
Totals	419,500	419,500

Information necessary to prepare the year-end adjusting entries appears below.

1. Depreciation on the office equipment for the year is $12,000.
2. Employee salaries are paid twice a month, on the 22nd for salaries earned from the 1st through the 15th, and on the 7th of the following month for salaries earned from the 16th through the end of the month. Salaries earned from December 16 through December 31, 2021, were $1,400.
3. On October 1, 2021, Pastina borrowed $54,000 from a local bank and signed a note. The note requires interest to be paid annually on September 30 at 12%. The principal is due in 10 years.
4. On March 1, 2021, the company lent a supplier $24,000 and a note was signed requiring principal and interest at 9% to be paid on February 28, 2022.
5. On April 1, 2021, the company paid an insurance company $8,000 for a one-year fire insurance policy. The entire $8,000 was debited to prepaid insurance.
6. $900 of supplies remained on hand at December 31, 2021.
7. A customer paid Pastina $1,000 in December for 1,620 pounds of spaghetti to be delivered in January 2022. Pastina credited deferred sales revenue.
8. On December 1, 2021, $2,400 rent was paid to the owner of the building. The payment represented rent for December 2021 and January 2022 at $1,200 per month. The entire amount was debited to prepaid rent.