7
advanced-math

A parabola has x-intercepts at -2 and 4. What is the x-coordinate of its vertex?

A

1

B

2

C

3

D

-1

Correct Answer: A

Choice A is the correct answer. Parabolas are symmetric. The axis of symmetry (and thus the vertex's x-coordinate) lies exactly halfway between the roots.

  1. Find the midpoint: −2+42\frac{-2 + 4}{2}.
  2. Simplify: 22=1\frac{2}{2} = 1.

Choice B is incorrect because it is the sum. Choice C is incorrect because it is not the midpoint. Choice D is incorrect because of sign error.

Next
Question 8 →
Back to Set
Set 8: Quadratic Equations and Functions 8