Question

Determine which relation is a function.

A.
{(–5, 1), (–5, 0), (–2, 1), (–1, 4), (6, 2)}

B.
{(–5, 1), (–2, 0), (–2, 2), (3, 4), (6, 2)}

C.
{(–5, 1), (–2, 0), (–1, 1), (2, 4), (6, 3)}

D.
{(–5, 3), (–2, 0), (–1, 2), (6, 4), (6, 3)}
how would i do this

Answer 1

In order for a relation to be a function all domains (or x-axis) must NEVER repeat

Answer 2

So which one of these examples DON'T have repeating numbers?

Answer 3

d

Answer 4

D has 2 "6"s

Answer 5

wait

Answer 6

c?

Answer 7

Yes!

Answer 8

could you explain to me a little more about functions

Answer 9

ok, for example

Take the coordinates (2, 3). We know it as 2 = x-axis and 3 = y-axis

A relation is basically just giving the x and y axis and different name

x-axis = domain and y-axis = range

Answer 10

And in order for a relation to be a function it must NEVER have a repeating domain

Answer 11

BUT, don't get confused with range (or y-axis). A range can have repeating numbers, just not the domain

Answer 12

For a function, no member of the domain set can map to more than one member of the range set. i.e. there cannot exist(a,b) and (a,c) when b and c are different. This rule is sufficient

Answer 13

Like I said though, the range can have repeating numbers

Answer 14

ooh okay i see