Please help.. I have no idea what I'm doing with this.. Can someone please explain how to use the exponential decay model?

Frank has $66.50 in his account on sunday. over the next week, he makes the following changes to his balance via deposits and purchases: day debit ($) credit ($) monday 60.33 80.75 tuesday 54.45 wednesday 49.20 15.00 thursday 35.40 friday 16.85 75.00 saturday 80.56 on what day does frank first get charged an overdraft fee? a. wednesday b. thursday c. friday d. saturday select the best answer from the choices provided a b c d

1. what is the formula for finding the vertical distance between two points on a coordinate plane?

Explain why the factor 1.5 is broke. into two numbers in the model.