The answer is: The first graph.
The explanation is shown below:
1. You have the following functions given in the problem above:
[tex]f(x)=-x+1[/tex]
[tex]f(x)=x+1[/tex]
2. You must give values to the variable "x" of both functions to obtain values of "y", as you can see in the table attached.
3. Then, you must plot each point obtained and you will have the first graph shown in the figure above.
