3
advanced-math

How many x-intercepts does y=x2+4y = x^2 + 4 have?

A

0

B

1

C

2

D

3

Correct Answer: A

Choice A is the correct answer.

  1. Set y=0y = 0: x2+4=0x^2 + 4 = 0.
  2. Solve: x2=4x^2 = -4.
  3. Since no real number squared equals a negative number, there are no real solutions.

Geometrically, this is a parabola shifted up 4 units, so it never touches the x-axis.

Choice B is incorrect because that happens if the vertex is on the axis. Choice C is incorrect because that happens if the vertex is below the axis (for upward opening). Choice D is incorrect because quadratics have at most 2.