# Alegebra- Function or NOT a function

if you have a relation with the domains: 0,1,2,3,4 and a range of: 3,1,2,4,2 does this mean it is not a function because there are two outputs of the number 2? Or can it only not be function if there are two of the same inputs with a different output?

• The second one. Sep 2, 2015 at 23:41
• It's not a function if for some value $x$ you'd have different values of $y$. Let's say you have a random function $f(x)$ and you plug in $x=1$, if it would show something like $f(1) = 2$ and $f(1)= 3$, it wouldn't be a function. The reverse is true though, wherein if you have $f(1)=2$ and $f(2)=2$, it would still be a function.
– mopy
Sep 2, 2015 at 23:48