To solve this problem you must apply the proccedure shown below:
1- You have that following parent function (the most basic function of the linear functions) given in the problem above:
f(x)=x
2- When you graph this parent function, you obtain the graph shown in the figure attached.
3- If you shift the linear parent function 7 units down, you have the following new function:
f(x)=x-7
4- The graph of the new function is shown in the second figure attached.
The answer is: f(x)=x-7
