Preparing and posting journal entries; and preparing a trial balance.?

Shelton Engineering completed the following transaction in the month of June.
Received a bill for rent of equipment that was used on a recently completed job. The 1,200 rent must be paid within 30 days.

Collected 7,200 cash in partial payment from the client described in transaction (g)
transaction (G)- Completed 12,000 of engineering services for a client . This amount is to be received in 30 days.
Paid 1,500 cash for wages to a drafting assistant
Paid 2,250 cash to settle the account payable created in transaction (h)
Transaction (H)- Purchased 2,250 of additional office equipment on credit.
Paid 675 cash for minor repairs to the drafting equipment
Shelton withdrew 9,360 cash for personal use
Paid 1,500 cash for wages to a drafting assistant
Paid 3,000 cash for advertisement in the local newspaper during June.

Received a bill for rent of equipment that was used on a recently completed job. The 1,200 rent must be paid within 30 days
Dr Equipment rental expense $1,200
Cr Equipment rental payable $1,200

Collected 7,200 cash in partial payment from the client described in transaction (g)
transaction (G)-
Completed $12,000 of engineering services for a client . This amount is to be received in 30 days
Dr Accounts receivable $12,000
Cr Engrg svcs revenue $12,000

Dr Cash $7,200
Cr AR $7,200

Paid 1,500 cash for wages to a drafting assistant
Dr Wages expense $1,500
Cr Cash $1,500

Paid 2,250 cash to settle the account payable created in transaction (h)
Transaction (H)-
Purchased 2,250 of additional office equipment on credit
Dr Office equipment $2,250
Cr AP $2,250

Dr AP $2,250
Cr Cash $2,250

Paid 675 cash for minor repairs to the drafting equipment
Dr Repairs expense $675
Cr Cash $675

Shelton withdrew 9,360 cash for personal use
Dr Owner's drawings $9,360
Cr Cash $9,360

Paid 1,500 cash for wages to a drafting assistant
Dr Wages expense $1,500
Cr Cash $1,500

Paid 3,000 cash for advertisement in the local newspaper during June
Dr Advertisement expense $3,000
Cr Cash $3,000

Trial balance at end June
Debits-
Equipment rental expense $1,200
AR $4,800
Wages expense $3,000
Office equipment $2,250
Repairs expense $675
Owner's drawings $9,360
Advertisement expense $3,000
Total debits $24,285

Credits-
Cash $11,085
Equipment rental payable $1,200
Engrg svcs revenue $12,000
Total credits $24,285

The info is missing the opening balances at June 1. If the firm received only $7,200, it could not have paid all those expenses as well as let the owner draw out $9,360. Because of this, the cash balance went into credit.