Answer and Explanation:
The Journal entries are shown below:-
1. Salary Expense $1,500
     To Salary Payable $1,500
(Being salary expense is recorded)
Here we debited the salary expenses as it increased the expenses and we credited the salary payable as  it also increased the liabilities
2. Salary Expense Dr, $2,100
  Salary Payable Dr, $1,500
       To Cash $3,600
(Being cash paid is recorded)
Here we debited the salary expenses and salary payable as it increased the expenses and decreased the liabilities  and we credited cash as it reduced the assets