Answer:
The change in the amount in Rachel's bank account due to the withdrawals can be represented by the integer -18. This is because she withdraws $18 each day for seven days, resulting in a decrease in the account balance.
On the other hand, if Rachel were to deposit $18 into her bank account once each day for seven days, the change in the account can be represented by the integer +18. This indicates an increase in the account balance.
The key difference between the integer for the withdrawals (-18) and the integer for the deposits (+18) lies in the direction of the change. The negative sign (-) represents a decrease or subtraction, indicating that the account balance is getting smaller due to the withdrawals. Conversely, the positive sign (+) represents an increase or addition, indicating that the account balance is growing due to the deposits.