Year end financial statement is assets $22,000 common stock $5,000 revenue $11,000 dividends $750 beginning retained earnings $3,750 ending retained earnings $6,000. The amount of liabilities reported on the end of period balance sheet was

Liabilities = Assets - Owners Equity.

So first thing you need to do is calculate Owners Equity, then you can calculate your Liabilities.

So it would be 11,000

Common Stock is $5,000
Ending Retained Earnings is $6,000
So Ending Owners Equity is $11,000 (5,000 + 6,000)
Liabilities = Assets of $22,000 - Owners Equity of $11,000
Liabilities = $11,000