Key Idea: Vertex / Maximum / Minimum

The vertex of a parabola is its highest or lowest point, depending on how it opens.

General Rule:

• For a quadratic function y=ax^2+bx+c:

  x=−(b/2a)

  gives the x-coordinate of the vertex.

• If a>0, the parabola opens up, and the vertex is a minimum.

• If a<0, the parabola opens down, and the vertex is a maximum.

Why this matters for the SAT:

Recognizing the vertex helps identify maximum or minimum values in quadratic functions.
It’s key for solving graphing, optimization, and real-world parabola problems efficiently