5
advanced-math

Solve: x26x+7=0x^2 - 6x + 7 = 0

A

3±23 \pm \sqrt{2}

B

6±26 \pm \sqrt{2}

C

3±23 \pm 2

D

3±2-3 \pm \sqrt{2}

Correct Answer: A

Choice A is the correct answer.

  1. Identify: a=1,b=6,c=7a=1, b=-6, c=7.
  2. Discriminant: (6)24(1)(7)=3628=8(-6)^2 - 4(1)(7) = 36 - 28 = 8.
  3. Formula: x=(6)±82(1)=6±222x = \frac{-(-6) \pm \sqrt{8}}{2(1)} = \frac{6 \pm 2\sqrt{2}}{2}.
  4. Simplify: Divide both terms by 2: 3±23 \pm \sqrt{2}.

Choice B is incorrect because it forgets to divide the 6 by 2. Choice C is incorrect because it simplifies 8\sqrt{8} as 2 (it is approx 2.82). Choice D is incorrect because it uses 6-6 instead of (6)-(-6).