Is this really the question: ?
If so, then the first rule I would apply is that
Then, you can remove a common factor of a:
ive got a really important maths exam on friday morning and ive just started going through some old maths papers again, and its been such a long time since i done some of it and im slightly stuck on simplifying this;
a^2 - 3ab * 2a + 6b ab
any help would be much apreciated