Functions

Mari and Lewis both have cell phone plans that give them each 10 gigabytes (GB) of data each month. The graph and table below show the remaining amount of data that Mari and Lewis have after each week in the month. 

At the Atkinson Farm, you can pick your own vegetables. You pay a small fee to enter the farm, and then you pay a price per pound of vegetables you pick. The graph below shows the total cost as a function of pounds of vegetables. 

The Jackson Farm also allows you to pick your own vegetables. You pay an entry fee of $15 and then $2.50 per each pound of vegetables you pick.

Two functions are shown below.

Function 1:  $${y={2\over3}x +1}$$

Function 2:  

Ella thinks that Function 2 has a greater initial value because $$3>1$$.
Tommy thinks that Function 2 has a greater rate of change because $$1\frac{1}{2} > \frac{2}{3}$$.

Both Ella and Tommy made a mistake in their thinking. Help each of them understand their mistake and make a new comparison. 

Cora and Daniel are both saving money each month. The total amount in their savings accounts is a function of the number of months they have been saving. Each account is represented below.

Cora: $${y=65x+100}$$, where $$y$$ represents the total amount and $$x$$ represents number of months 

Daniel: