<P> Rearranging this yields: </P> <Dl> <Dd> Spending = Income--Net Savings = Income + Net Increase in Debt </Dd> </Dl> <Dd> Spending = Income--Net Savings = Income + Net Increase in Debt </Dd> <P> In words: What you spend is what you earn, plus what you borrow . If you spend $110 and earned $100, then you must have net borrowed $10 . Conversely if you spend $90 and earn $100, then you have net savings of $10, or have reduced debt by $10, for a net change in debt of--$10 . </P>

What are the four sources of aggregate demand