Note: I used the rule that a^2 + b^2 = (a - bi)(a + bi). I recommend FOILing out the right hand side to confirm the equation is true. You'll use the idea that i^2 = -1.
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
