On the x-y coordinate plane there is a parabola, y=x(4-x). Which of the following points is in the region that is enclosed by this parabola and the x-axis?
I. (1, 2) II. (2, 5) III. (3, 2)
Answers:
A) I only	B) II only	C) III only	D) I and III	E) I, II, and III
Since co-efficient of x^2 is negative, the parabola will be downward facing. So the parabola and the x axis will enclose some points where the y-values of the parabola are positive.   When x = 1, y = 3 lies on the parabola, so (1, 2) will be enclosed by the parabola and x axis.   When x = 2, y = 4 lies on the parabola, so (2, 5) will not be enclosed by the parabola and x axis.   When x = 3, y = 3 lies on the parabola, so (3, 2) will be enclosed by the parabola and x axis.   The answer is I and III.
<result>D</result>
On the x-y coordinate plane there is a parabola, y=x(4-x). Which of the following points is in the region that is enclosed by this parabola and the x-axis?
I. (1, 2) II. (2, 5) III. (3, 2)