Answer:
Please see the attached snapshots for the answers.
Step-by-step explanation:
a.
Debit: Cash $30,000
Credit: Service Revenue $30,000
To record Service Revenue.
b.
Debit: Supplies $20,000
Credit: Accounts Payable $20,000
To record purchase of supplies on account.
c.
Debit: Salaries Expense $7,000
Credit: Cash $7,000
To record salaries Expense.