Re: Is it true that it's better to do bad in Mathematics than alrights in General Mat
No.
Doing poorly in a subject will negatively impact your atar, no matter what subject it is. If you are consistently getting <50 raw in 2u, you probably aren't going to go that well and it'd be better to drop to general and get >75%.
To get a band 6 in general, you need to get 98+ raw in the hsc external, and if you perform average you will be scaled down to a greater extent than if you performed average in 2u.