Part A
What is the 2010 federal income tax for a single person whose taxable income that year was 4000 dollars?
The function is
T(x)=0.1x
so
For x=4,000
substitute
T(x)=0.1*(4,000)
T(x)=$400
Part B
What is the 2010 federal income tax for a single person whose taxable income that year was 170000 dollars?
the function is
T(x)=0.28x-6,290.75
For x=170,000
substitute
T(x)=0.28*(170,000)-6,290.75
T(x)=$41,309.25
Part C
What is the taxable income for a single person whose 2010 federal income tax was 105000 dollars?
The function is
T(x)=0.28x-6,290.75
For T(x)=105,000
substitute
105,000=0.28x-6,290.75
solve for x
0.28x=105,000+6,290.75
0.28x=111,290.75
x=$397,466.96