An examination of the ledger shos this error:
The Service Revenue account was totaled at $5200 instead of $5280. How do I correct this on a T-account?

I don't understand how the error took place, which makes a difference. If it quite literally was just added incorrectly, just cross out the wrong answer and write in the correct one.

Could you please not double-post your questions like this. It's just a cause for confusion, and someone else had already answered your questions.