Why does y=9x+1 describes y as a function of x

If you are just building your payment history, how many points from a perfect score will you possibly miss?

Ricky takes out a $31,800 student loan to pay his expenses while he is in college. after graduation, he will begin making payments of $190.66 per month for the next 30 years to pay off the loan. how much more will ricky end up paying for the loan than the original value of $31,800? ricky will end up paying $ more than he borrowed to pay off the loan.

Luke wants to reduce the area of his rectangular garden by 1/4 the expression 14/w can be used to represent this change. what is another way to write this expression?