Set 10: Quadratic Equations (Intermediate)

Explanation

Answer: A

Which equation has roots that sum to 0?

$x^2 - 9 = 0$

✓ Correct

$x^2 - 9x = 0$

$x^2 + 9x = 0$

$(x - 3)^2 = 0$

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Roots sum to 0 when the linear term $b$ is 0. * A: $x^2 - 9 = 0 \Rightarrow x = \pm 3$ . Sum = $3+ (-3) = 0$ . * B: Sum = 9. * C: Sum = -9. * D: Roots are 3, 3. Sum = 6. Choice B is incorrect because sum is 9. Choice C is incorrect because sum is -9. Choice D is incorrect because sum is $3 +3=6$ .

Key Steps:

•

The correct answer is $x^2 - 9 = 0$

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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