For every function you need evaluate the function for every value in the domain D. And the collection of this values correspond to the range of the function.
1. 
2. 
3. 
4. 
Answer: Our required formula becomes :

Step-by-step explanation:
Since we have given that

We need to write a formula for f(b) in terms of b So, it becomes

Hence, our required formula becomes :

I hope this helps you
f (1+1)= f (1)+8
f (2)= 27+8
f (2)=35
f (2+1)= f (2)+8
f (3)= 35+8
f (3)=43