1.domain={1,3,6} range={2,5,8} yes it is a function
2.domain={3,2} range={7,13} no it’s is not a function
3.domain={0,2,4} range={-1,1,3,5} no it is not a function
4. 0 ride=$0 1ride=$3 2ride=$6 3ride=$9 4ride=$12 5ride=$15
Yes it is a function
(If you want me to explain I can)
Hope this helps
Have a great day/night
