Set 6: Quadratic Equations (Advanced)

Explanation

Answer: A

Find the axis of symmetry for $y = -2x^2 + 8x - 1$ .

$x = 2$

✓ Correct

$x = -2$

$x = 4$

$x = -4$

Detailed Explanation

Choice A is correct. Choice A is the correct answer. The axis of symmetry for a parabola $y = ax^2 + bx + c$ is the vertical line $x = -b/2 a$ . 1. Identify: $a = -2, b = 8$ . 2. Substitute: $x = -8 / (2(-2))$ . 3. Simplify: $x = -8 / -4 = 2$ . Choice B is incorrect because of a sign error. Choice C is incorrect because it forgets the 2 in the denominator. Choice D is incorrect because of both errors.

Key Steps:

•

The correct answer is $x = 2$

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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