02: Quadratic Functions 

\
Ordered pair: a set of independent (x) values that represent a relationship

Relation: a set of inputs (x) and outputs (y)

Function: a relation with one output (y) for each input (x) and no x value may be repeated

\
# Identifying Functions

With points: no x values can be the same or repeat

With a graph: must pass the vertical line test

→ Vertical line test: draw a vertical line through the graph, cutting through it. If it intersects at more than 1 point then it fails the test and thus is not a function

\
# Function Notation

The way that a function is written → **f(x)** is essentially our new y

f(x) can also be a value, f(value), and you would then substitute that value in for x

\
# Domain and Range of Functions

* Domain: every x value your function is allowed to be
* Range: every y value your function is allowed to be

Use:

**