In the amount of 12100. I have about 5 questions like that and the beginning balance for accounts payable (in the general ledger) is 7500 and with the other transactions it was looking okay but it this one is a credit then my account will be negative.

Accounts Payable will have a normal credit balance. When you purchase something on account you will credit the account balance, which will increase the account balance, while a payment on account will be a debit to your balance, which will decrease your account balance.

Accounts Receivable will have a normal debit balance, which means that when a customer purchases something from you on account you will debit your account balance, which increases your account balance. When a customer makes a payment on his or her account this you credit the account, which will decrease your account balance.

So I can have a negative amount in my general ledger?

No, you will only have debits and credits with either a debit balance or a credit balance.

So what if I added and subtracted and got a negative number that doesn't mean anything?