Algebra I Recipe: Functions and Relations

A. Definitions

1. Relation – a set of ordered pairs ie.
2. Domain – the x-values of the relation. (1,3,5)
3. Range – the y-values of the relation. (2,4,6)

B. Identifying Relations that are Functions

1. A relation is a function if no ordered pair has the same x-value.
2. The graph of a relation is a function if a vertical line touches the graph at only one point, as the vertical line passes over the graph. (Vertical Line Test)

C. Evaluating a Function (that’s in equation form)
         **f(x) replaces y and is read "f of x"

1. Substitute the given x-value in for x.
2. Simplify by using order of operations.