Question

fine the domain of f(x)^-1 if f(x) = 4x-8

Answer 1

i want to assume this is the inverse of f, but juts to make sure... is this the inverse of f or 1/f(x)?

Answer 2

f(x)

Answer 3

Looks like they want an inverse function.

Answer 4

y = 4x-8

Solve for x.

(y-8)/4 = x

y/4 - 2 = x

Change the y to x, and change the x to y.

y = x/4 -2

f(x)-1 = x/4-2

Can someone verify this please?

Answer 5

I've gotten much better at these!

Answer 6

These are answer choices x≠ 0

x≠ 1/4

x≠ -4

All real numbers

Answer 7

Well my guess would be all real numbers for the inverse function.

What do the rest of you guys think?

Answer 8

both the function and the inverse are lines. so yes, all real numbers...

Answer 9

@Lib Libs

"I've gotten much better at these!"

Awesome, I'm glad to hear it!

Ex: 1 inverse functions: http://tutorial.math.lamar.edu/Classes/Alg/InverseFunctions.aspx

Answer 10

I'm working on these and the one's with fractions :/

Answer 11

got another one you're stumped on?

Answer 12

Let f(x) = x^2 + 6 and g(x) = x + 8 over x find (g of f)(4)

Answer 13

g(x^2+6) = (x^2+6) +8

=x^2 +14

g(f(4)) = (4)^2 +14

= 30

Answer 14

55/63

15/11


11/15

63/55
Are answer choices

Answer 15

Does this problem have to do with inverses? Do you have a screenshot?

Answer 16

Yes inverse's http://i1204.photobucket.com/albums/bb402/Libby_Williams/Yoyoyo.jpg

Answer 17

Weird b/c it doesn't mention anything about inverses. But I'll just solve it that way and see if I stumble on something.

Answer 18

Maybe its not

Answer 19

nope, its just function composition

Answer 20

Yes thats what it is?

Answer 21

@AccessDenied did you come up with a different answer from what I got?

Answer 22

Sorry ; - ;

Answer 23

i dont think you took into account the (x+8) / x, like i did the first time i went through it and got the same answer

Answer 24

I didn't see the "over x." I wasn't paying attention lol.

Answer 25

i didnt catch it either, and i was confused why it wasnt in the answers. :P
it does seem like it goes to be 22+8 / 22, which is 30/22 or 15/11

Answer 26

Let f(x) = x^2 + 6 and g(x) = x + 8 over x find (g of f)(4).

g(f(4)):

I'll just find f(4) and then plug it into g.

f(4) = 16 +6 = 22

g(22) = (22+8)/22 = 30/22
=15/11