Omar is putting money into a checking account. Let y represent the total amount of money in the account (in dollars). Let x represent the number of weeks Omar has been adding money. Suppose that x and y are related by the equation 450+20x=y.

Answer the questions below.
Note that a change can be an increase or a decrease.
For an increase, use a positive number. For a decrease, use a negative number.
What is the change per week in the amount of money in the account?
What was the starting amount of money in the account?