I want to get into the RMIT course which is Environmental and Sustainable Engineering, it has on its prerequisite that you need Math Methods or specialist with a study score of 20 and over to go into it, is it a must?
EDIT: Reason why, because i'm doing further maths.
To be perfectly honest with you, you might be wise to have a look at some other opportunities than engineering if you're sincerely worried about doing methods. Maths is a vital component of engineering, making it really hard to enjoy if you don't enjoy maths and don't excel at maths.
It's great that you're interested in the environment and sustainability. There are plenty of environmental science courses that will still allow you to follow your passion in these fields, without having quite as heavy reliance on maths (though it must be said that maths is pretty closely married to any science).
I'm sorry to be so blunt, but yeah, engineering ≈ maths