Ok, (not trying to come off as rude) this website has a rule,
https://www.askmehelpdesk.com/financ...board-b-u.html ,that we can't give you answers until you first show us that you at least gave a try at your homework questions. Once you do this we can help you more in detail. Since you seem confused though I will try to provide you with some questions to answer so that you can show you attempted to answer these questions and we can tell you if you are right or wrong and provide a detailed explanation.
#1
He debited 750 to prepaid insurance instead of insurance expense. Will this change the balance at all? Meaning will this make the trail balance (debits must equal credits) unbalanced? If it does how much does it make it unbalanced? Which one (debit or credit column) has more in it that made it unbalanced? Yes, these are the instructions you posted but I just tried to make them a little more understandable.
#2
A purchase of supplies were made. Instead of posting $250 worth of supplies he posted $25 worth and credited cash for only $25 as well. Ask yourself the questions I asked for question #1 and try to answer them on here for more help. Good luck and I'll wait for your reply so I can help you more in detail.