Refer to the accounts listed below:

a. Accounts Recievable

b. Accounts Payable

c. Cash

d. Equipment

e. Notes Payable

f. Rent Expense

g. Salaries Expense

h. Service Revenue

For each of the accounts, idicate the normal balance of the account and the effect of a debit or credit on the account.

I know the answers, I'm just not sure why Rent Expense and Service Revenue are considered credits. Can you explain?