I have a question..so failing a unit and then getting a good mark when repeated is better than passing with a 50?
Depends to which purpose as achre rightly points out.
To employees? No idea. It might look better to show that you do indeed have the capability and were just having some issues the first time you took it (or it might not, i have no idea).
Money wise, you still have to pay for it even if you pass (not a huge deal i guess). GPA/WAM wise, what achre says is also correct, if it averages out to higher than 50 with your second attempt, it is good.
Also, if you fail, you get the credit points returned to you. It's good or bad based on perspective. Maybe that area of study just wasn't for you and thats why you failed. You can now use those credit points to do another subject and excel in it.
¯\_(ツ)_/¯
Have a play around with this: WAM, GPA (4.0), HWA Calculator (MONASH)
You can't "undo" a fail though, unless you've transferred out of a course and you don't it across with you, afaik.
Regarding undoing things, it depends.
Few ways you could achieve that. I believe for Med admissions, they only look at your last three years (full time equivalent i think) of study. So, if you add on an extra diploma or do honours, it kind of would "undo" your first year results. If you do both those things (diploma and honours) it'll probably "undo" your first two years depending when you add the diploma and the structure of your degree.
As Achre also points out, if you transfer, you can *choose* which units you take with you, which units you want to claim credit for. So, in theory you could leave your lowest units off that transfer form but say you leave 4-5 off, that means you have 4-5 extra units to do. I am not sure but if you're transferring internally (within the same uni), i dont know if its ever totally obliterated from your transcript. It still might show your old degree units even if you transfer out of them and later don't credit them. If you transfer to a new uni, they'll be totally wiped but people might also asked to see your old transcript.