Answer: 

Explanation:
- A function is a relation in which every input associates with an unique output.
 
Let x denotes the input values and y denotes the output values.
As per the given we have the following table :
 x y
 0 4 
 1 3
 3 1
 4 0
We can see that the sum of each x and corresponding y is 4.
i.e. x+y= 4
Since we write the function in terms of independent variable (x) to show dependent variable (y).
So our function becomes , 

So the rule for a function with inputs, 0,1,3,4 and outputs 4,3,1,0 would be 
