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

yes, this is a much clearer picture. Thanks. I am actually struggling to look at your previous solution steps :)

Candice, remember that it’s vertical against horizontal.

“When a graph of y against x...” means y is the vertical and x is the horizontal.

“When a graph of x against y...” means x is the vertical and y is the horizontal.

Oh yes, I left out part ii.

y = 3x^2 divided by (x - 4)

When y = 48,

48 = 3x^2 divided by (x - 4)
48 (x - 4) = 3x^2
16 (x - 4) = x^2
16x - 64 = x^2
0 = x^2 - 16x + 64
0 = (x - 8) (x - 8)
x = 8

Thank you so much, Mr Eric. I know where is my mistake now. Thanks and have a good evening too. Take care :)