Answer:
Jan-02	
Dr Bulldozer	$ 250,000	
 Cr Cash $ 20,000
 Cr Note Payable $ 230,000
Jan-03
Dr Bulldozer	$ 20,000	
 Cr Accounts Payable $ 20,000
Jan-30	
Dr Accounts Payable	$ 20,000	
 Cr Cash $ 20,000
 
Feb-01	
Dr Repair and Maintenance Expense	$ 800	
Cr Cash $ 800
 
Mar-01
Dr Computer Software	$ 3,600	
Cr Cash $ 3,600
Explanation:
Preparation of the journal entries for each of the above transactions.
Jan-02	
Dr Bulldozer	$ 250,000	
 Cr Cash $ 20,000
 Cr Note Payable $ 230,000
(Purchased bulldozer) 
Jan-03
Dr Bulldozer	$ 20,000	
 Cr Accounts Payable $ 20,000
(Replaced tracks on bulldozer)
 
Jan-30	
Dr Accounts Payable	$ 20,000	
 Cr Cash $ 20,000
(Paid cash)	
 
Feb-01	
Dr Repair and Maintenance Expense	$ 800	
Cr Cash $ 800
(Repaired seat of bulldozer) 
Mar-01
Dr Computer Software	$ 3,600	
Cr Cash $ 3,600
(Purchase computer software)