First year to find how much one pencil cost cost then multiply A number
1. You have the function 
2. You know that
with
, because the division by zero is not defined. So ,
for
where
is a integer number.
3. Then, to find the domain of the function given in the problem, you must make 
Where
is odd number.
4. Therefore:

5. Finally, the domain is: 
The answer is: 