I have to fill out the missing spots in this spreadsheet for my accounting class... I already figured out the missing assetts, liabilities, and owners equity numbers easily using the accounting equation (Assetts= liabilities + owners expense)

Company X
Beg of Year
Owners Equity=80

End of Year
Owners Equity=60

Expenses for the year=100

How do I calculate revenues?
Also, if it gave me revenues and not expenses, how would I calculate expenses for that year?

Thanks, any help is greatly appreciated!