Thank you so much for your response. I actually got the same answer as you but the answer key shown otherwise. The answer sheet says answer for (i) should be y = 3x^2/x-4 and answer for (ii) should be 8. Thus, I was wondering if the question is wrong or my answers (which is also the same as yours) are wrong :(

No, this is incorrect.

Candice, the “x-axis” here is actually the vertical axis. I send you my working in a moment. Let me find it.

Thanks Mr Eric :)

Thank you