2U is my worst subject lol
Have you thought about completing a bridging course to consolidate your mathematical knowledge?
USyd's Mathematics Extension 1 briding course is suitable for
students intending to study an engineering course, or major in mathematics, computer science or physics. USyd also states:
This Extension 1 bridging course is for you if you have done Mathematics (2-unit) in the HSC and want to enrol in a course which has an assumed knowledge of Extension 1 Mathematics (3-unit)
The University has courses available to help you develop the pre-requisite knowledge that some courses require. Discover what science and mathematics bridging courses are available.
www.sydney.edu.au
Similarly, UNSW's Mathematics bridging course
is for you if you have no prior knowledge of HSC Mathematics Extension 1 and intend to pursue maths-related courses in the first year of your degree.
Strengthen your knowledge in the key areas required for your first year of study with UNSW Science Bridging courses.
www.science.unsw.edu.au
Bridging courses can familiarise you with essential knowledge you need to have, particularly in your first year of uni, which can make your first year a less difficult/overwhelming experience.