# Quadratic Vocabulary for Algebra II

## Vertex

Definition: The point at which the axis of symmetry intersects a parabola.

## Axis of Symmetry

Definition: A line about which a quadratic function (parabola) is symmetric. The equation used to find the axis of symmetry is shown below.

## Maximum Value

Definition: The y-coordinate of the vertex of the quadratic function

f(x)=a^2 + bx + c, where a<0

## Minimum Value

Definition: The y-coordinate of the vertex of the quadratic function

f(x)=ax^2 + bx + c, where a>0

## Standard Form

Definition: A quadratic equation written in the form: ax^2 + bx+ c=0, where a, b, and c are integers, and a cannot = 0

## Vertex Form

Definition: A quadratic function in the form y= a(x-h)^2 + k, where (h,k) is the vertex of the parabola and x=h is its axis of symmetry.

## Intercept Form

Definition: y=a(x-r1)(x-r2)

## Completing the Square

Definition: All quadratic equations can be solved using the Square Root method Property by manipulating the equation until one side is a perfect square, which is called "completing the square". You are changing the equation from standard form to vertex form.

Follow the Steps below to Complete the Square:

1. Put () around ax^2 + bx

2. Factor the a value from x^2 and x

3. Take 1/2 the middle term and square it

4. Add the number and it's opposite

5. Factor perfect square trinomial

6. Rewrite in the form y= a(x-h)^2 + k (which is vertex form)