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

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)?

f(x)

Looks like they want an inverse function.

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?

I've gotten much better at these!

These are answer choices x≠ 0 x≠ 1/4 x≠ -4 All real numbers

Well my guess would be all real numbers for the inverse function. What do the rest of you guys think?

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

@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

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

got another one you're stumped on?

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

g(x^2+6) = (x^2+6) +8 =x^2 +14 g(f(4)) = (4)^2 +14 = 30

55/63 15/11 11/15 63/55 Are answer choices

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

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

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.

Maybe its not

nope, its just function composition

Yes thats what it is?

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

Sorry ; - ;

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

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

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

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

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