1.

Use the fact that, the domain of a function is the set of all input values.

Here, for this function the input values are taxable income.

So, the set of all taxable income values is the domain of the function.

Therefore,

Use the fact that, the range of a function is the set of all output values.

Here, for this function the output values are Income tax due values.

So, the set of all Income tax due values is the range of the function.

Therefore,