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Math Help - Find f(3m - 4) + 3

  1. #1
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    Find f(3m - 4) + 3

    If f(x) = x^2 - 2x + 4, find f(3m - 4) + 3.
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  2. #2
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    Quote Originally Posted by magentarita View Post
    If f(x) = x^2 - 2x + 4, find f(3m - 4) + 3.
    sub 3m-4 in for x: (3m-4)^2 - 2(3m-4) + 4

    9m^2 - 24m + 16 - 6m + 8 + 4 +3 = 9m^2 - 30m + 31
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  3. #3
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    Quote Originally Posted by magentarita View Post
    If f(x) = x^2 - 2x + 4, find f(3m - 4) + 3.

    f(x) = x^2 - 2x + 4

     f(3m-4)=(3m-4)^2-2(3m-4)+4

    =9m^2-24m+16-6m+8+4

     =9m^2-30m+28

     <br />
f(3m - 4) + 3=9m^2-30m+28+3=9m^2-30m+31<br />
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  4. #4
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    ok

    Great but where does the 3 come in?

    f(3m - 4) + 3

    When do I add 3?
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  5. #5
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    Simply add it to whatever you get for {\color{blue}f(3m-4)} .

    So: {\color{blue}f(3m-4)} + {\color{red}3} = {\color{blue}9m^2-30m+} \underbrace{{\color{blue}28} + {\color{red}3}}_{\text{Add}} = 9m^2 - 30m + 31

    as what the other posters got.
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  6. #6
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    ok

    Quote Originally Posted by o_O View Post
    Simply add it to whatever you get for {\color{blue}f(3m-4)} .

    So: {\color{blue}f(3m-4)} + {\color{red}3} = {\color{blue}9m^2-30m+} \underbrace{{\color{blue}28} + {\color{red}3}}_{\text{Add}} = 9m^2 - 30m + 31

    as what the other posters got.
    It all makes perfect sense to me now. Thank you.
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