Question

Help with functions where you have F(X)= ## find what X is... Example in Comments

Answer 1

t(x)=0.25(x-7900)+79
The equation represents the tax bill [t] of a single person who's adjusted gross income (AGI) is x dollars between 7900 and 31600 inclusive.
a. What is a single filer's tax bill if AGI is x=20,000
b. What is a single filer's AGI if the tax bill is 2540

I really need help with b.

Answer 2

b. What is a single filer's AGI if the tax bill is 2540

so they give you the tax bill of t(x) = 2540 and they want you to use this to find x

Answer 3

t(x)=0.25(x-7900)+79

2540=0.25(x-7900)+79 ... replace t(x) with 2540

2540-79=0.25(x-7900)+79-79

2461 = 0.25(x-7900)

I'll let you finish

Answer 4

ugh.. i was wayyyyyy over thinking this... thanks that helps a ton.

Answer 5

17744=x

Answer 6

you are correct, so x = 17,744 is the adjusted gross income (AGI) when the tax bill is t(x) = 2540

Answer 7

okay so if I had to write this as an ordered pair it would be (17,744, 2450)

Answer 8

sorry it didn't notify me til now

Answer 9

yes but one important thing

if you are going to write the numbers in an ordered pair, do NOT use a comma in 17,744. The fact that a commas is used to separate x and y means you cannot use one to make "17,744" more readable.

(17,744, 2450) looks like an ordered triple, ie a point in 3d space

so write (17744, 2450) instead