Question

.

Answer 1

Are you seeing any x in your expression??

Answer 2

In f(3), 3 is x as you represent your function as f(x), so value inside brackets of f, will be x..

So, here x = 3..

And you have : f(x) = x - 7

Here where, you see x, just replace it with 3 and check what you got.. :)

Answer 3

Oh wow..! Going good..

Yes, solve it further.. :)

Answer 4

How, -4/3??

Answer 5

Yes, then you will write : For x = 3

f(3) = 3 - 7

f(3) = ??

Answer 6

-4

Answer 7

Yes, that's it..

f(3) = -4

Answer 8

Them?? Whom ??

Answer 9

Hey, that is representation of function.

f(x) is general representation of any function, f(x) does not mean (x) is getting multiplied with f..

Answer 10

Ohhh okayy got it

Answer 11

So is the final answer f(3) = -4?

Answer 12

Whenever you will write function, you will write like : f(x), g(y), h(z) etc..

Answer 13

In f(3), it does not imply 3 is multiplied with f and don't find f here in any way..

Yes, f(3) = -4 is your final answer..

Basically, f(x) = x - 7 means that at x, your function f has value of x - 7

f(3) = -4 means at x = 3, your function will have value of -4..

Answer 14

So the inverse of f(x) = 4x – 7

Answer 15

Is this the same question??

How does 4 come with x here??

Answer 16

That's what the original equation is, f(x) = 4x – 7

Answer 17

Okay..

Here, there is a standard procedure to find f inverse, Oh wait..

Answer 18

What the hell..!! My mistake, sorry..

I thought the question is f(x) = x - 7..

Sorry, sorry..

Yes, there you will multiply 4 with x surely..

Answer 19

So was the first part wrong?

Answer 20

f(x) = 4(3) – 7 which I switch it to that?

Answer 21

Yes, sorry..

f(x) = 4x - 7

f(3) = 4(3) - 7

f(3) = 12 - 7

f(3) = 5

Answer 22

Okay got it! As for the inverse I think I got it on my own, could you just check my work?

Answer 23

This is now correct, I earlier misinterpreted the question, Sorry...

Answer 24

Yeah, sure go ahead..

Answer 25

Oh wait f(x) should be replaced with y my bad

Answer 26

Ughh i feel like I did it wrong

Answer 27

Yeah stuck and confused:(

Answer 28

Don't worry, I am here to make it correct.. :)

Answer 29

Thank you

Answer 30

First write the function given:

f(x) = 4x - 7
Now, put f(x) = y (Not x, you did wrong here itself)

so, you get : y = 4x - 7

Now, find x in terms of y here:

y + 7 = 4x - 7 + 7

y + 7 = 4x

Divide by 4 both the sides:

\[x = \frac{y+7}{4}\]

Now, change x with y and y with x:

\[y = \frac{x+7}{4}\]

This y is now f inverse, so replace y here with \(f^{-1}(x)\)

So, finally you will get:

\[f^{-1}(x) = \frac{x + 7}{4}\]

Answer 31

Omg thanks so much your a lifesaver!

Answer 32

Getting all that??

Answer 33

Yeah I am!

Answer 34

Will you try one if I give one to you??

Answer 35

I'll try:P I still have to work on another problem

Answer 36

It will not take much time, instead it will clear your concepts..

Find inverse for f(x) = 3x + 2

Answer 37

and then subtract to on both sides, so -2 = 3y

Answer 38

How you got 3y ??

Answer 39

or wait y - 2 = 3y?

Answer 40

I just subtracted two on both sides

Answer 41

Put f(x) = y and not x = y..

Answer 42

See, you have f(x) = 3x + 2

Just replace f(x) with y, not x with y here..

You will get : y = 3x + 2 f(x) and x are two different things..

Answer 43

Ohhh okay I understand

Answer 44

So I subtract 2 now right? to make it y - 2 = 3x?

Answer 45

Yeah going good, proceed further..

Answer 46

Find x there in terms of y..

Answer 47

Then I divide 3x to make it x = y - 2/3x

Answer 48

You will divide with 3 only..

Answer 49

Why 3x ??

Answer 50

and then switch around the x and the y so its y = x - 2 / 3

Answer 51

Yes, though you got it right, here just replace y with f inverse of x..

Answer 52

so then f-1(x) = y = x - 2/3