P$5-67$A$.($Learning Objective $6$: Using the aging approach for uncollectibles$)$ The September $30,20$X$7,$ records of Effective Communications include these accounts: Accounts Receivable. $\backslash$$$270,000$ Allowance for Doubtful Accounts. $\backslash ((9,100)\backslash )$ At year$-$end $($December $31),$ the company ages its receivables and adjusts the balance in Allowance for Doubtful Accounts to correspond to the aging schedule. During the last quarter of $20$X$7,$ the company completed the following selected transactions: Nov. $30$ Wrote off as uncollectible the $\backslash (\backslash$$ $1,100\backslash )$ account receivable from Black Carpets and the $\backslash (\backslash$$ $500\backslash )$ account receivable from Old Timer Antiques. Dec. $31$ Adjusted the Allowance for Doubtful Accounts and recorded doubtful$-$account expense at year$-$end, based on the aging of receivables, which follows. $[$P$5\mathrm{.}67]$ What are the balances for the following accounts: $(1)$ net account receivables and $(2)$ bad debt expense?