9
advanced-math

Which equation has roots that sum to 0?

A

x2−9=0x^2 - 9 = 0

B

x2−9x=0x^2 - 9x = 0

C

x2+9x=0x^2 + 9x = 0

D

(x−3)2=0(x - 3)^2 = 0

Correct Answer: A

Choice A is the correct answer. Roots sum to 0 when the linear term bb is 0.

  • A: x2−9=0⇒x=±3x^2 - 9 = 0 \Rightarrow x = \pm 3. Sum = 3+(−3)=03 + (-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=63+3=6.

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Set 12: Quadratic Equations and Functions 12