Question

Christie has $200 in her bank account. Every month, she deposits $20 into her account.

The equation of the line that models the amount of money, y, in her account x months from now is y = x .

Answer 1

y = 20x + 200

Explanation:

The 200 is the constant. It is only added once, but the monthly deposits are added at 20 every month.

After 1 month:

y = 20x + 200

y = 20(1) + 200

y = 20 + 200

y =220 money deposited.

After 2 months:

y = 20x + 200

y = 20(2) + 200

y = 40 + 200

y =240 money deposited.

After 3 months:

y = 20x + 200

y = 20(3) + 200

y = 60 + 200

y = 260 money deposited

And so on, and so on, and so on...