Algebra II Honors Homework Help

[darshanpatel]

The inverse of f(x)= k(-x^3 -4x -9) is a function and f^-1(7)=1. What is the value of k?


Work is a picture: http://tinypic.com/view.php?pic=29xj4i8&s=5


Mod note: Too large picture deleted


Final Answer: k= (4y+10)/-7

 

[SammyS]

The inverse of f(x)= k(-x^3 -4x -9) is a function and f^-1(7)=1. What is the value of k?


Work is a picture: http://tinypic.com/view.php?pic=29xj4i8&s=5
...

Final Answer: k= (4y+10)/-7

Hello darshanpatel. Welcome to PF.

What is y ?? (Your answer makes no sense.)

Here's a hint: If \displaystyle f^{-1}(7)=1\,, then what is \displaystyle f(1)\,?

Note: When a moderator of these forums sees the size of that image, he/she will likely delete it.

 

[darshanpatel]

The y is from exchanging the x and y's to get the inverse, also can you please help me and not hint lol.

 

[SammyS]

The y is from exchanging the x and y's to get the inverse, also can you please help me and not hint lol.

LOL indeed!

Read the rules of these Forums.

By the way: The hint I gave should lead you directly to the solution.

 

[Evo]

There is a template that should be used for homework. Next time, please fill it out instead uf uploading a picture.

Picture copied.

 

[SammyS]

There is a template that should be used for homework. Next time, please fill it out instead uf uploading a picture.

Picture copied.

Thanks Evo !

 

[darshanpatel]

LOL indeed!

Read the rules of these Forums.

By the way: The hint I gave should lead you directly to the solution.

I don't understand the hint... Do I plug it directly in or something?

There is a template that should be used for homework. Next time, please fill it out instead uf uploading a picture.

Picture copied.

Also Another PF mod or something said it was ok...

 

[SammyS]

I don't understand the hint... Do I plug it directly in or something?

If \displaystyle f^{-1}(7) = 1\,, \ \ \text{ then }\ f(1) = 7 \,. Understand ?

 

[darshanpatel]

So I plug 1 into x variables and make whole equation = to 7?

 

[SammyS]

So I plug 1 into x variables and make whole equation = to 7?

Yes. Then solve for k.

 

[darshanpatel]

Thank you, you are really smart. :)

 

[Mark44]

Also Another PF mod or something said it was ok...

If it is much larger than 800 x 600 pixels, the moderators will likely delete it.

 

[darshanpatel]

ok, thanks...