for this to be a growth function it has to be any number that is latger than zero
FOR EXAMPLE :-
50% which equals to 0.5
Let x be the number of texts (amount of texts) Carly does in a month.
Let y be the "total" amount Carly will have to pay in a month.
Then, as per the TURKEY plan, Carly's monthly total cost will be represented by the equation as shown: 
As we can clearly see in the above equation even if Carly does not text a single message (when x=0), even then they will have to pay $20 for that month.
For the GOBBLE plan, the equation will be:
.
In this plan as there is no fixed charge, Carly wont have to pay anything extra if they dont make a call.
Answer:
Can u show the whole question