4
algebra

Find the value of kk if the line through (1,2)(1, 2) and (3,k)(3, k) is perpendicular to y=2xy = 2x.

A

11

B

33

C

−2-2

D

66

Correct Answer: A

Choice A is the correct answer. Perpendicular slope.

  1. Target Slope: Perpendicular to 2 is −1/2-1/2.
  2. Line Slope: k−23−1=k−22\frac{k-2}{3-1} = \frac{k-2}{2}.
  3. Equate: k−22=−12\frac{k-2}{2} = -\frac{1}{2}.
  4. Solve: k−2=−1→k=1k-2 = -1 \rightarrow k = 1.

💡 Strategic Tip: Set up the slope formula equal to the target slope.

Choice B is incorrect.Choice C is incorrect.Choice D is incorrect.

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Linear Functions Set 95