Received a bill from Hemlock Gas and Electric Co. in the amount of $137.89 on account. I know that you should debit the Utilities Expense and credit the Accounts Payable, but how do you post to the subsidiary ledger?? Please help me.

It would be usual to have the creditors account in the sub-ledger and to post the entry to that. The Accounts Payable account in the General Ledger acts as as control account for the subsidiary ledger so that all entries in the General Ledger are also posted in the subsidiary ledger. Where you have multiple entries in, say, a Cash Payments Journal, or a Purchases Journal, only the Total would appear in the General Ledger and the individual entries in the subsidiary ledgers