What is the double entry system?​

Double-entry bookkeeping, in accounting, is a system of book keeping where every entry to an account requires a corresponding and opposite entry to a different account. The double-entry system has two equal and corresponding sides known as debit and credit. The left-hand side is debit and the right-hand side is credit. In a normally debited account, such as an asset account or an expense account, a debit increases the total quantity of money or financial value, and a credit decreases the amount or value. On the other hand, for an account that is normally credited, such as a liability account or a revenue account, credits increase the account's value and debits decrease that value

The federal reserve took an expansionary approach during the crisis. this was done by expanding the money supply and boosting liquidity. this can be seen in the fed's actions of lending to banks, purchasing securities, and lowering the federal funds rate in order to lower overall interest rates. the fed's goal was to increase consumer spending and overall liquidity within the system, and they pursued this by expanding the supply of liquid money.