Help me with this pls

The mean of a set of data is -3.82 and its standard deviation is 2.31. find the z score for a value of 3.99.

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

7x+8y=-18, 4x-9y=-3 solve the system of equations