The income tax in a country is determined according to the taxable net income of the taxpayer. This is, the amount of money remaining of your gross income after all the deductions and exemptions that the taxpayer is entitled to claim according to their economic situation.

The following scale is used to determine your income tax.

If the net income subject to contribution is:	The contribution will be:
less than $9,000	0%
more than $9,000, but less than $25,000	7% of the $9,000 excess
more than $25,000, but less than $41,500	$1,120 plus the 14% of the $25,000 excess
more than $41,500, but less than $61,500	$3,430 plus the 25% of the $41,500 excess
more than $61,500	$8,430 plus the 33% of the $61,500 excess

1. Write the domain function f(x) that describes the scale. The x is the variable that measures the net income subject to tax, and the y is the income tax determined by the scale.

2. Explain in your own words the function and how is a determined income amount applied.

3. Graph the function.

4. Determine, using the function, the income tax of the next contributors giving their net income subject to tax.

name of the contributor:	net income subject to tax
Jenny	$7,500
Joseph	$23,750
Nicholas	$43,600
Enoch	$85,000