Can someone please explain how to do this? (photo)

To be able to do this is you would choose any numbers the best number would be -1,0,1,2 that would be in the column of x. Then the next column that means from the numbers you chose you would just plug it in for example f(x)=7-x x=2 f(2)=7-x, plug in the 2for x it would look like f(2)=7-2=5 f(x)=5. I hope that helps!