Cisco Systems, Inc. had the following transactions for June 2023:

• Sold networking equipment for $250,000 on account.
• Provided installation services worth $100,000, to be paid next year.
• Received $50,000 in advance for a service contract to be performed in July 2023.
• Paid salaries of $30,000, with an additional $15,000 accrued.

Required:

1. Record these transactions in the general ledger.
2. Prepare the necessary adjusting entries at year-end.
3. Discuss the importance of revenue recognition principles and adjusting entries in financial accounting.