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Math Help - [SOLVED] (f o h)(x)

  1. #1
    Junior Member moonman's Avatar
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    [SOLVED] (f o h)(x)

    f(x) = x^2 + 4
    h(x) = 2x - 1/ x + 3

    Find (f o h)(x)

    (f o h)(x) = f(h(x))

    f(2x-1 / x +3) = (2x-1 / x +3)^2 + 4

    f(2x-1 / x +3) = (4x^2 - 4x + 1 / x^2 + 6x +9 ) + 4

    Did I do this correctly?
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  2. #2
    Moo
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    Hello,
    Quote Originally Posted by moonman View Post
    f(x) = x^2 + 4
    h(x) = 2x - 1/ x + 3

    Find (f o h)(x)

    (f o h)(x) = f(h(x))

    f(2x-1 / x +3) = (2x-1 / x +3)^2 + 4

    f(2x-1 / x +3) = (4x^2 - 4x + 1 / x^2 + 6x +9 ) + 4

    Did I do this correctly?
    Yes

    But you can also put 4 in the fraction :

    \frac{4x^2-4x+1}{x^2+6x+9}+4=\frac{4x^2-4x+1+4(x^2+6x+9)}{x^2+6x+9}
    and then expand
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  3. #3
    Junior Member moonman's Avatar
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    Quote Originally Posted by Moo View Post
    Hello,

    Yes

    But you can also put 4 in the fraction :

    \frac{4x^2-4x+1}{x^2+6x+9}+4=\frac{4x^2-4x+1+4(x^2+6x+9)}{x^2+6x+9}
    and then expand
    ahh! Thank you
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