I am doing closing entries and here is the instructions I was given:

Wages accrued total 15 hours worked at $8.50 per hour

Here is the adjusting entry I think it is:

Salaries and Wages Expense 127.50
Salaries and Wages Payable 127.50

Am I on the right track?

Indeed you are.

In some cases the entry might include credits to various payables for the payroll taxes withholdings that'll apply to the salary, with the credit to "Salary and Wages Payable" then being just for the expected net pay.

In the absence of any payroll tax rates or other info, though, your entry is correct. The important thing is that you've debited a Salaries expense account, and credited liability(ies) in the same amount (even if the liabilities will eventually be paid in the form of net pay checks and various tax payments for the withholdings).