Great thread EulerFan101 but there are a few errors in it:
Do I need to include units?
You should always include units - make sure to the read the initial information and the question you're on to know what units you're working with, and what units you should report your answer to. They're not always the same.
VCAA
do not expect you to include units with any Extended Response questions, both for intermediate steps and final answer. You can even be penalized for including the wrong units, whereas you won't be if you include none at all.
This doesn't mean they can't randomly ask you "What are the units of the answer above", or having a MC question that has 2+ options as the same number but different units (with only one of them being the right answer).
Do I HAVE to give the domain for an inverse function?
As a general rule, you should. However, if they say "find the rule for ", then you HAVE to give it, and in other cases you don't have to unless they also specify the domain. But just to be safe, you should.
If they
only ask you to find the
rule, you only need to specify the inverse functions equation.
If they ask you for the
function, specifying the domain alongside with the rule is required.