Example
An on-line comic book retailer charges shipping costs according to the following formula
S(n)={1.5n+2.5 if 1≤n≤140 if n≥15
Draw a graph of the cost function.
Answer:
First, draw the line S(n)=1.5n+2.5. We can use transformations: this is a vertical stretch of the identity by a factor of 1.5, and a vertical shift by 2.5.

S(n)=1.5n+2.5
Now we can eliminate the portions of the graph that are not in the domain based on
1≤n≤14

S(n) = 1.5n+2.5 for 1=n=14
Last, add the constant function S(n)=
0 for inputs greater than or equal to
15. Place closed dots on the ends of the graph to indicate the inclusion of the end points.
In the following video we show how to graph a piecewise defined function which is linear over both domains.
https://youtu.be/B1jfpiI-QQ8