Examples

[(-5,2), (3,0), (3,4)]

[(x,y), y = 2x-1]

x = y^2

The domain (input) is the set of x values of the ordered pairs. The range(output) is the y value of the ordered pairs.

A function is a relation such that for each x value there is one and only one value of y.

Example

x I y

______________

3^2 I +9 or -9 This is a relation and not a function.

Y = x^2 is a function, if you graph it you get a parabola.

x – 4y = -4 is a function if you graph it you get a straight line.

A test is if you can draw a vertical line through the graph and hit two spots you don’t have a function, you have a relation.