They offer two plans.
Plan A.
The membership fee of $5, and $1 for every DVD.
This can be expressed as
[tex]y=1\cdot x+5[/tex]
Where x represents DVDs.
Plan B.
A monthly cost of $25 for unlimited DVD rentals.
This can be expressed as
[tex]y=25[/tex]
Because the second plan B doesn't depend on the number of DVDs.
The image below shows the graph.
As you can observe in the image above, they have a total cost of $25 when they rent 20 DVDs.
