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Math Help - f o g = h.

  1. #1
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    f o g = h.

    If f(x) = 2x + 8 and h(x) = 2x2 + 2x + 6, find a function g such that f g = h.

    I thought I had a handle on these questions until I got to this one. I have an answer but I am 95% sure it isnt right.

    ((x^2)/2)-14x-26

    Like I said I am pretty sure its not right.
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  2. #2
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    Does g(x)=x^2+x-1 work? Why or why not?
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  3. #3
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    Wow I am an idiot. I tend to overcomplicate things greatly. Thanks haha.
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  4. #4
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    Quote Originally Posted by Plato View Post
    Does g(x)=x^2+x-1 work? Why or why not?
    Can you please clarify this for me !
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  5. #5
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    Its a function f(g(x))=h correct? So you take the function of g, which in this case we found to be x^2+x-1 and plug that into the x values of f(x).

    Doing so will give you 2(x^2+x-1)+8.
    Factoring out will give you 2x^2+2x-2+8, add like terms and you will come to h, which is 2x^2+2x+6!
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  6. #6
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    Quote Originally Posted by Aladdin View Post
    Can you please clarify this for me !
    Well is it true that f \circ g(x) = h(x)?
    Now you must understand function composition to do that.
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  7. #7
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    Quote Originally Posted by ryan18 View Post
    So you take the function of g, which in this case we found to be x^2+x-1
    You guessed !! g(x)
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  8. #8
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    Quote Originally Posted by Plato View Post
    Well is it true that f \circ g(x) = h(x)?
    Now you must understand function composition to do that.
    Yes , for sure .
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