Functions: Domain and Range

How can you write out the function notation for exercise 3a question 3 which takes an input of income and gives an output of tax payable?

What problem are you having? If the rule was that all income over 10,000 was taxed at 5%, would you be able to express that as a function?

Also, you realize that the question does not ask for you to write the function, just to analyze it?