1. Cash received from a customer on account was debited for $760, and Accounts Receivable was credited for the same amount. The actual collection was for $670.
2. The purchase of a printer on account for $340 was recorded as a debit to Supplies for $340 and a credit to Accounts Payable for $340.
3. Services were performed on account for a client for $700. Accounts Receivable was debited for $70 and Service Revenue was credited for $700.
4. A debit posting to Salaries and Wages Expense of $775 was omitted.
5. A payment on account for $206 was credited to Cash for $206 and credited to Accounts Payable for $260.
6. Payment of a $600 cash dividend to Crane Company's stockholders was debited to Salaries and Wages Expense for $600 and credited to Cash for $600.
7. The amounts for two accounts with normal balances were listed in the wrong column.

I suppose that the requirement is correcting the errors in postings by a way of journal entries.

Debit  Accounts receivable $90

  Credit  Cash                                  $90

Dr Printer asset account        $340

  Cr Supplies                                         $340

Debit Accounts receivable     $670

Debit salaries & wages           $775

Credit account payable            $54

Debit retained earnings            $600

  Credit salaries and wages              $600

Explanation:

Actual cash received was $670 but $760 was posted to both accounts,hence $90 should credited to cash $90 and the same debited to accounts receivable.

Credit of $340 to accounts payable was correct,only the debit entry needs be reversed by crediting supplies and debiting Printer account.

The entry for revenue was correct but the debit was for a wrong amount.Hence Debiting accounts receivable with $630 takes care of that.

Salaries and wages would debited with $775

Accounts was debited $260 instead of $206,hence we credit accounts payable with $54 ($260-$206)

The dividends debited to salaries and wages should be reversed by crediting salaries and wages and debiting retained earnings