What is the meaning of f '' (4) = -4?

It means that the second derivative of the function "f" when x=4 (or when the argument of the function is 4) is negative 4.

Explanation:

after lydia compare her check register to her bank statement, and the ending balances do not seem to match. then, she must make a bank reconciliation by putting the data all together.

to do this, she need to determine the bank ending balance. after, add the deposits in transit then deduct the outstanding checks. moreover, if the actual checkbook balance does not equal this number, check again for transporting errors by subtracting the balances and add the difference to nine. sometimes, a mathematical error can happen but a bank reconciliation is a great tool to resolve the discrepancies.