Question

A function is given: f(x) = 3x + 12. I know the inverse (g(x)) is 1/3x - 4 already (unless I did something wrong lol). Part b says, "Use composite functions to show these functions are inverses." I know that means to use the unfilled-in circle, but I'm not entirely sure what to do

Answer 1

The inverse is wrong.

Answer 2

Oh, can you help me with it? I just found a website saying it should be (x-12)/3. Is that right?

Answer 3

Wrong. But incredibly close.

Answer 4

Omg lol

Answer 5

You just put the numbers/terms in different places.

Answer 6

So (x-3)/12?

Answer 7

Wait omg lol u were right. I just tested my function and it was wrong...

Answer 8

*facepalms*

Answer 9

(x-12)/3 I mean.

Answer 10

Omg lol Hakuna Matata, I screw up all the time too. So how can I show them an inverses using composite functions? I don't get that stuff

Answer 11

Do you mean finding the inverse?

Answer 12

No, I meant the "use composite functions" part. Do they want me to use the little degrees thingy?

Answer 13

You just do (f o g)(x)

Aka f(g(x)

Answer 14

So yes.

Answer 15

Oh so they want me to multiply them?? Why didn't they just say so? lol

Answer 16

Erm No

Answer 17

It means first you do g, then f that result.

Answer 18

But how can I do (x-12)/3? Like solve for g?

Answer 19

Just plug in a number.

Answer 20

Ohhhhhhhh okay. In the next part they give me -2. If I do the work for part b, can I just claim it as work for part c also or is there different work to do? In part c they tell me to evaluate f(g(-2)) then explain what the domain is

Answer 21

Do you understand domains and ranges?

Answer 22

Yes, I got that down. It's like the only thing in Algebra I CAN do lol

Answer 23

Than just find the domain.

Answer 24

Okay cool. Thanks!