Blackhorse Productions, Incorporated, used the aging of accounts receivable method to estimate that its Allowance for Doubtful Accounts should be $21,950. The account had an unadjusted credit balance of $11,100 at that time. a. The appropriate bad debt adjustment was recorded. b. Later, an account receivable for $2,100 was determined to be uncollectible and was written off. Required: For each transaction listed above, indicate the amount and direction (+ for increase or for decrease) of effects on the financial statement accounts and on the overall accounting equation. (Enter any decreases to Assets, Liabilities, or Stockholders Equity with a minus sign.) Assets Liabilities Stockholders' Equity a. Allowance for Doubtful Accounts = + Bad Debt Expense b. = + ++ b