Answer:
You need to deduct $450 from the company's cash balance. Since the check was received from a client, it covered an accounts receivable, so the adjusting entry should be as follows:
XX/YY, adjusting entry to reconcile checking account:
Dr Accounts receivable 450
Cr Cash 450
Accounts receivable and cash both have debit balances, and since you want to increase accounts receivable you must debit it, while you must credit cash in order to decrease it.