One of the common forms for quadratic functions is called vertex form, because it highlights the coordinates of the vertex of the function's graph.

Sal rewrites the equation y=-5x^2-20x+15 in vertex form (by completing the square) in order to identify the vertex of the corresponding parabola. Created by Sal Khan and Monterey Institute for …

Learn how to graph any quadratic function that is given in vertex form. Here, Sal graphs y=-2 (x-2)²+5. Created by Sal Khan.

Since the vertex is the point at which a parabola changes from increasing to decreasing or vice versa, it is also either the maximum or minimum y -value of the parabola.

Graph quadratic functions that are given in the vertex form a (x+b)²+c. For example, graph y=-2 (x-2)²+5.

The reason why I knew it was a parabola, in particular a downward-opening parabola, is when you look at what's going on here. This is written in vertex form but it's a quadratic.

Sal rewrites a quadratic equation in vertex form and shows how it reveals the vertex of the corresponding parabola. Created by Sal Khan and Monterey Institute for Technology and Education.

Is there a formula for finding the vertex of a parabola? Is there a video on that topic?

In tests and other scenarios where you're asked to graph a parabola the most important things to get right will always be the location (s) of the zero (s) and the vertex.

We've seen linear and exponential functions, and now we're ready for quadratic functions. We'll explore how these functions and the parabolas they produce can be used to solve real-world problems.