Inputs: -13, 20, 0, -4, 11, -1, 17, (blank space)
Outputs: -15, -11, -9, -2, -1, 5, 5, 13
We have the points
(-13, -15) ( 20, -11) ( 0, -9) ( -4, -2) ( 11, - 1) (-1, 5) ( 17, 5) ( x, 13)
We cannot have the same x going to two different y's
So
-5 is OK
-1 is not ...we would have ( -1,5) and (-1. 13)
0 is not......we would have ( 0, - 9) and (0, 13)
2 is OK
11 is not....we would have ( 11, -1) and (11, 13)
17 is not....we would have (17,5) and (17,13)