Please show the formulas, I am unsure on how to go about this.

5 E17-18 (Impairment of Debt Securities) Hagar Corporation has municipal bonds classified as available- for-sale at December 31, 2013. These bonds have a par value of $800,000, an amortized cost of $800,000, and a fair value of $720,000. The unrealized loss of $80,000 previously recognized as other compre- hensive income and as a separate component of stockholders' equity is now determined to be other than temporary. That is, the company believes that impairment accounting is now appropriate for these bonds. Instructions (a) Prepare the journal entry to recognize the impairment. No entry is needed to adjust accumulated other comprehensive income. (b) What is the new cost basis of the municipal bonds? Given that the maturity value of the bonds is $800,000, should Hagar Corporation amortize the difference between the carrying amount and the maturity value over the life of the bonds? (c) At December 31, 2014, the fair value of the municipal bonds is $760,000. Prepare the entry (if any) to record this information