Answer and Explanation:
According to the scenario, computation of the given data are as follow:-
Interest paid semiannually on July 31, and Jan 31, 
so the rate of interest is :- 9% × 6÷12 = 4.5%  and  8% × 6÷12 = 4%
Date    Interest         Paid interest 4%         Amortized         Carrying value
        expenses 4.50%                             discount amount
February,1                                                    $735,474
July,31	$33,096   -   $32,400                    $696            $736,170
Jan.31      $33,128   -   $32,400                    $728            $736,898
Working note =
Paid interest = $810,000 × 4÷100 = 32,400
Interest expenses in July,31 = $735,474 × 4.5 ÷ 100 
= 33,096.33 or $33,096
Interest expenses in January,31 = $736,170 × 4.5÷100 
= 33,127.65 or $33,128
Carrying Value = Previous Carrying Value + Amortized Discount Amount
July,31 
= $735,474 + $696
= $736,170
Jan,31 =  $736,170 + $728 = $736,898
Journal Entry
Feb,1  Cash A/c Dr. $735,474
   Discount on bonds payable A/c Dr. $74,526
   To bonds payable A/c      $810,000
          (To Record the issuance of bond)
July,31  Interest expense A/c Dr. $33,096
      To Discount on bonds payable A/c  $696
      To Cash A/c $32,400
             (To Record the interest expense)
Dec,31  Interest expense A/c Dr. $27,606
       (9% × 5÷12) × $736,170
      To Discount on bonds payable A/c $606
      To Cash A/c $27,000    (8% × 5÷12) × $810,000  
            (To Record the accrued interest)
Jan,31  Interest expense A/c Dr. $5,522
     Interest payable A/c Dr. $27,000
     To Cash A/c $32,400
     To Discount on bonds payable A/c $122
  ($728 - $606) = $122
           (To Record the interest on January)