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Homework Help: Algebra II Honors Homework Help

  1. Dec 9, 2011 #1
    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
     
    Last edited by a moderator: Dec 9, 2011
  2. jcsd
  3. Dec 9, 2011 #2

    SammyS

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    Hello darshanpatel. Welcome to PF.

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

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

    Note: When a moderator of these forums sees the size of that image, he/she will likely delete it.
     
  4. Dec 9, 2011 #3
    The y is from exchanging the x and y's to get the inverse, also can you please help me and not hint lol.
     
  5. Dec 9, 2011 #4

    SammyS

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    LOL indeed!

    Read the rules of these Forums.

    By the way: The hint I gave should lead you directly to the solution.
     
  6. Dec 9, 2011 #5

    Evo

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

    Picture copied.
     

    Attached Files:

  7. Dec 9, 2011 #6

    SammyS

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    Thanks Evo !!!
     
  8. Dec 9, 2011 #7
    I dont understand the hint... Do I plug it directly in or something?

    Also Another PF mod or something said it was ok...
     
  9. Dec 9, 2011 #8

    SammyS

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  10. Dec 9, 2011 #9
    So I plug 1 into x variables and make whole equation = to 7?
     
  11. Dec 9, 2011 #10

    SammyS

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    Yes. Then solve for k.
     
  12. Dec 9, 2011 #11
    Thank you, you are really smart. :)
     
  13. Dec 9, 2011 #12

    Mark44

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    If it is much larger than 800 x 600 pixels, the moderators will likely delete it.
     
  14. Dec 10, 2011 #13
    ok, thanks...
     
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