4. Suppose that you after 3 months you have $350 in yor account and after 7 months you have $650.

- a) Let x denote the number of months the and let y denote the amount of money in the account. Find a linear equation which will predict how much money you will have in the account as a function of the number of months
- b) Graph this function.
- c) Use this function to determine how much money you will have after 12 months.

a) If we l et x denote the number of months the and let y denote the amount of money in the account, then

and

To find a linear equation, first find the slope.

Next, use the point-slope form of the equation

To solve for y, remove parentheses,

and add 350 to both sides

This would tell you how much money you would have in your account if you opened the account with $125 and put in $75 each month (and there was no interest accumulating).

c) To compute the amount after 12 months, we plug in a 12 for the x in the equation.