When you set the equations together, you get x^2-3x-10. You then set this equation equal to zero and get (x-5)(x+2) or x=-2 and x=5. Then, plug these x-values into each equation to get your y-values.
If during a given month your average daily credit card balance is $800 and your yearly interest rate is 17%, then the interest you owe on your credit card for that month would be: $11.33
