8
advanced-math

Which equation has an axis of symmetry at x=3x = 3?

A

y=x2−6x+5y = x^2 - 6x + 5

B

y=x2+6x+5y = x^2 + 6x + 5

C

y=x2−3x+5y = x^2 - 3x + 5

D

y=2x2−6x+5y = 2x^2 - 6x + 5

Correct Answer: A

Choice A is the correct answer. We check x=−b/2ax = -b/2a for each option.

  • A: −(−6)/2(1)=6/2=3-(-6) / 2(1) = 6/2 = 3. (Correct)
  • B: −6/2(1)=−3-6 / 2(1) = -3.
  • C: −(−3)/2(1)=1.5-(-3) / 2(1) = 1.5.
  • D: −(−6)/2(2)=6/4=1.5-(-6) / 2(2) = 6/4 = 1.5.

Choice B is incorrect because axis is x=−3x=-3. Choice C is incorrect because axis is x=1.5x=1.5. Choice D is incorrect because axis is x=1.5x=1.5.

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Set 6: Quadratic Equations and Functions 6