Question

I think the asnwer is 8

Answer 1

actually is 3 cranes and 1 toucan

Answer 2

Given the function f(x) = 3(x+2) - 4, solve for the inverse function when x = 2.

i did this f(2) = 3(2 + 2) - 4
and then this
f(2) = 6 + 6 - 4
f(2) = 12 -4
f(2) = 8

Answer 3

what? @jdoe0001

Answer 4

there are the answer choices

−4
0
4
8

Answer 5

well, so lets re-write this. with y instead of f(x). because all f(x) means here is the y.

\(\Large\color{blue}{ y=3(x+2) - 4}\)

Answer 6

first switch the x and y. I mean literally switch x and y

Answer 7

okay

Answer 8

what do you get?

Answer 9

you have
\(\Large\color{blue}{ \color{red}{y}=3( \color{green}{x}+2) - 4}\)
when you switch x and y you get,
\(\Large\color{blue}{ \color{red}{x}=3( \color{green}{y}+2) - 4}\)

Answer 10

Now, solve for y.
Like make the function y= something ...

okay?

Answer 11

so i can make y any number or i have to solve for y?

Answer 12

no, you have to solve for y.
you are to rearrange the equation in terms of y.

Answer 13

Like
y= ....

Answer 14

y = 8

Answer 15

f(2) = 8

Answer 16

like if I had
\(\Large\color{blue}{ \color{red}{x}=4 (\color{green}{y}-4) +4}\)
this is what I do,
\(\Large\color{blue}{ \color{red}{x}=4 \color{green}{y}-16+4}\)

\(\Large\color{blue}{ \color{red}{x}=4 \color{green}{y}-12}\)

\(\Large\color{blue}{ \color{red}{x}+12=4 \color{green}{y}}\)

\(\Large\color{blue}{ \frac{1}{4} \color{red}{x}+3=\color{green}{y}}\)

So, we get, \(\Large\color{blue}{ \color{green}{y}=\frac{1}{4} \color{red}{x}+3}\)

Answer 17

The function you have to solve for y, is,

\(\Large\color{blue}{ \color{red}{x}=3(\color{green}{y}+2)-4}\)

Answer 18

x = 26

Answer 19

we aren't plugging anything for x, we just want to solve for y.

Answer 20

(like I did in my example)

Answer 21

is that wrong?

Answer 22

and @12man, we really need a \(\Large\color{black}{ f^{-1}(2)}\), not \(\Large\color{black}{ f^{}(2)}\)

@iamabarbiegirl can you solve for y, or you don't understand what I want from you?

Answer 23

(f^-1 is a notation for the inverse function. )

Answer 24

go ahead....

Answer 25

now i'm lost (sorry)

Answer 26

Again, the function f(x) was,
\(\Large\color{blue}{ \color{green}{y}=3(\color{red}{x}+2)-4}\)
(and it is in terms of y)

Now, I am switching the \(\Large\color{blue}{ \color{red}{x}}\) and the \(\Large\color{blue}{ \color{green}{y}}\)

\(\Large\color{blue}{ \color{red}{x}=3(\color{green}{y}+2)-4}\)

Now, you need to solve for y.
(not by switching x and y to where they were, but by multiplying subtracting dividing.. or whatever....)

Answer 27

lets do the first step together.
\(\Large\color{blue}{ \color{red}{x}=3(\color{green}{y}+2)-4}\)

can you expand the parenthesis on the right side?

Answer 28

so i need to find x to solve for the first one and i need to find y to solve the second?

Answer 29

no no, you need to find the y in terms of x.

Answer 30

If you don't know what that means, then follow my directs and (for now) expand the parenthesis on the right side.

\(\Large\color{blue}{ \color{red}{x}=3(\color{green}{y}+2)-4}\)

\(\Large\color{blue}{ 3(\color{green}{y}+2)}\) is expanded to ?

Answer 31

okay, I'll push it a little further :D

\(\Large\color{blue}{ \color{red}{x}=3(\color{green}{y}+2)-4}\)

when you expand the \(\Large\color{blue}{ 3(\color{green}{y}+2)}\) you get \(\Large\color{blue}{ 3\color{green}{y}+6}\). right?

So after expanding parenthesis on the left hand side, we get,

\(\Large\color{blue}{ \color{red}{x}=3\color{green}{y}+6-4}\)

simplifying.... (we get)

\(\Large\color{blue}{ \color{red}{x}=3\color{green}{y}+2}\)

Answer 32

good with this so far? (see what I have done up and till now?)

Answer 33

I mean expanding parenthesis on the right side, said the left side, don't know why)

Answer 34

okay so i got y = 5x - 3/2

Answer 35

I don;t really get where you are getting the above from -;(

Answer 36

i did this
y = 2x + 3 /5
I flipped x and y so i got this
x = 2y + 3/5
multiplied 5 in both sides so i got this
5x = 2y + 3
subtracted 3 so i got
5x -3 = 2y +3 - 3
5x - 3 = 2y
devided 2 in both side so i got
5x - 3 /2 = y

Answer 37

so your initial function f(x), was
\(\Large\color{blue}{ \color{green}{f(x)}=2\color{red}{x}+\frac{3}{5}}\) ?

Because I saw that it is
\(\Large\color{blue}{ \color{green}{f(x)}=3(\color{red}{x}+2)-4}\)

that is what your first question syas.

Answer 38

and for your last step, you are correct, but don't divide both sides by 2, rather divide EACH TERM by 2.

this way you get
\(\Large\color{blue}{ \color{green}{y}=\frac{5}{2}\color{red}{x}-\frac{3}{2}}\)

Answer 39

So when your initial function is,

\(\Large\color{blue}{ \color{green}{f(x)}=2\color{red}{x}-\frac{3}{5}}\)

then the inverse (as we found), going to be (notice my notation for the inverse function )

\(\Large\color{blue}{ \color{green}{f^{-1}(x)}=\frac{5}{2}\color{red}{x}-\frac{3}{2}}\)

Answer 40

lost?

Answer 41

http://www.coolmath.com/algebra/16-inverse-functions/05-how-to-find-the-inverse-of-a-function-01.htm

try this link, maybe it will help you. it is the most simple one that I found that explains it.

Answer 42

sorry i lost connection but thanks

Answer 43

it's just a pre-test so it's okay

Answer 44

as long as you understand the concept, it is okay. Do you get all of this?

Answer 45

just a little not a lot but it's because i never learned this and this is a pre test so thats why

Answer 46

Well, all you need to do. (this is easy, because don't involve many steps) is:
given any f(x).

1) re-write the function with y instead of f(x). (Since f(x) is the same thing as y).
2) switch the y and the x.
3) solve/rearrange the new equation (after switching x and y with each other), to make it y=.... (as we did in this post before).
4) when you get your answer, then state your function is \(\large\color{black}{ f^{-1}(x) }\). (instead of saying that it is f(x). since \(\large\color{black}{ f^{-1}(x) }\) is the correct notation for an inverse function.

Answer 47

Next time though, try to be more clear about what you are trying to find... because I am still confused about your initial function -:(

anyways... good luck with whatever you are doing.

Answer 48

thanks and okay sorry

Answer 49

its alright