Set 7: Quadratic Equations

Explanation

Answer: A

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

✓ Correct

-1

Detailed Explanation

Choice A is correct. 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: $\frac{-2 + 4}{2}$ . 2. Simplify: $\frac{2}{2} = 1$ . 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.

Key Steps:

•

The correct answer is 1

Why others are wrong:

B: Choice B is incorrect and may result from a calculation error.

C: Choice C is incorrect and may result from a calculation error.

D: Choice D is incorrect and may result from a calculation error.

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