It's pretty standard actually for a good 2 Unit class: there is no real solution. It's in the same basket as 2( x + 3 ) = 2x + 6. For this, x is an element of the set of real numbers (and complex numbers too for ext 2). One is a solution where no real values are true, while the other, all values are true.
Next you'll try and convince me that parallel lines never meet.
Anyway, to the original poster:
What textbook have you been using? If you want to see whether you can reasonably handle 4 Unit / Extension 2, get the Cambridge 3 Unit books and see how you go at the Extension sections (which are an excellent treatment and preparation for the Harder 3 unit questions in the 4 unit course). If you can get through some of these questions, you are getting close to 100% on your 2 unit work and performing well in Extension 1, then definitely give Extension 2 a go. You can always drop back down if you are doing enough units - I would consider carefully however if dropping down was not an option.
As for the exam and coursework, as others have said most of the exam is procedural with the last couple of questions requiring ingenuity, elegance of solution or even just a little luck to complete within the time frame. However, the course does require a lot of practise that you will find time consuming (it is after all taking up almost half of your HSC). You need to be dedicated though so as you can perform quickly in both the exams you will do. Most good students can get close to full marks if given enough time. The fact is though that you aren't provided with this.
Anyway, hope this helps. And by the way, yes, some of those Q7 and Q8 exam questions are absolutely horrid. The way how the subject is scaled though picks up the slack.
Best Regards
Herremann
