9
advanced-math

What is the minimum value of y=x2+4x−1y = x^2 + 4x - 1?

A

-5

B

-1

C

-2

D

3

Correct Answer: A

Choice A is the correct answer. The minimum value is the y-coordinate of the vertex.

  1. Find x-coordinate: x=−4/2(1)=−2x = -4 / 2(1) = -2.
  2. Substitute x=−2x = -2: y=(−2)2+4(−2)−1y = (-2)^2 + 4(-2) - 1.
  3. Calculate: y=4−8−1=−5y = 4 - 8 - 1 = -5.

Choice B is incorrect because it is the y-intercept. Choice C is incorrect because it is the x-coordinate. Choice D is incorrect because of calculation errors.

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Set 6: Quadratic Equations and Functions 6