5
advanced-mathIf a parabola opens downward and has a vertex at , how many x-intercepts does it have?
A
2
B
1
C
0
D
Cannot be determined
Correct Answer: A
Choice A is the correct answer.
- Vertex: is above the x-axis (y is positive).
- Direction: Opens downward.
- Conclusion: Since it starts above the axis and goes down, it must cross the x-axis twice.
Choice B is incorrect because that requires vertex on x-axis. Choice C is incorrect because that requires vertex below x-axis (for downward). Choice D is incorrect because the geometry is fixed.