We should note that the bond investment account is recorded at cost by the Bondholder or Investor.
The cost or price is calculated as:
Cost = $90,000 * 86.4%
Cost = $90,000 * 0.864 = $77,760
Therefore, the entry to record should be:
debit Held-to-Maturity Investment in Bonds for $77,760 and credit Cash for $77,760