Puzzling math question for experts.

<p>I think number 11 or 12, in the 16 question Math section.</p>

<p>x^2-5x+6=(x-3)(x-2). So the parabola has x-intercepts at x=2 and x=3. It is facing upwards because the coefficient of x^2 (a hidden 1) is positive. This is enough information to see that both I and III are correct. Clearly II is wrong since a vertical line can intersect a function at most once. So there is a flaw in this question.</p>

<p>Alright, thanks a lot DrSteve!</p>

<p>We either have the question wrong (but I doubt it, since most people confirm the authenticity), or the question is flawed and it won’t be counted when scoring.</p>

<p>Thank you to all your contributions, this thread is answered.</p>