Relations and Functions

Relation is any set of ordered pairs.

ex) {(2,6),(-7,7),(4,3),(-7,2)}

X 0 1 2 3 4 5 6
Y 0 1 2 3 4 5 6

X--------M
Y--------N
Z--------O


y=2x+5
"the set of ordered pairs such that y is twice x"

all of these relations are functions except one. The first one isn't a function because it fails the vertical line test.