Answer:
Step-by-step explanation:
 
        
             
        
        
        
The orange is the original and the blue is the reflection over y=1
 
 
        
        
        
20: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200
14: 14, 28, 42, 56, 70, 84, 98, 112, 126, 140
140 is the smallest number they have in common.
        
             
        
        
        
We won't have a function if for same value of x in (x,y) we get different values y. 
So first step: figure out k so that the first coordinate (x) is the same:
3k-4=4k    | solve for k
k = -4
no check the values y for the elements of the relation
x = 3k-4 = -12-4=-16
so at -16 we get (-16,16) and (-16, 32), which mean for k=-4 the relation is not a function. 
Let me know if you have any questions.