12. domain= 4, 8, 8, 12, 12, 16, 20
range= 1, 1 ,2, 2, 3, 4, 3
it is not a function because it repeats x- values
13. x= 13, 17, 22, 25, 33
y=33, 25, 22, 25, 33
this is a function
14. x=1, 5, 5, 7, 11, 11
y= 2, 2 , 4, 6, 6, 8
this is not a function because x-value repeats itself