Replying to MATH HELP - ILL PAY WHOEVER HELPS ME

ok well im completely dumbfounded by this math project i have to do . . and ill ship whoever helps me out a couple dollars, cuz i have to get this done tonight cuz i leave for arizona tomorrow .

heres the deal:

Your a freshman in college and have a credit card with a limit of $7,000. the annual interest is 12% compounded monthly. You are required to make a minimum monthly payment on your unpaid balance.

then:
-on spring break you spend $1500
-in a car accident and then you buy a new used for for $6500, and insurance pays for $1000 of it
-you now reached your $7000 limit. you then cancel your credit card.

Part I: you think you can make a monthly payment of %40. Develop a model that will determine the balance on the account each month. Then determine
-how long it will take to pay off your debt
-why the Mastercard company wont be happy if you continue to pay only $50 a month

^for that i got a sequence equation of @font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 10pt; line-height: 115%; font-size: 11pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } U0 = 7000, Un = (1 + 0.12/12) x Un-1 – 50 , but my calculator wont allow me to graph it idk why. what should i use for the table?

ill put up part II if this get answered . remember . who helps will get a couple dollars mailed to them after i come back from arizona. haha. ill have you PM me your address