Set 9: Quadratic Equations (Intermediate)

Choice A is correct. Choice A is the correct answer. * A: The vertex requires calculation ($h=-b/2 a$) and is not immediately visible. * B: The y-intercept is simply $c$. (Visible) * C: The direction is determined by the sign of $a$. (Visible) * D: The stretch is determined by the magnitude of $a$. (Visible) Choice B is incorrect because $c$ is the y-intercept. Choice C is incorrect because $a$ determines direction. Choice D is incorrect because $a$ determines stretch.