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Math Help - Writing a function in standard form to find the vertex.

  1. #1
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    Writing a function in standard form to find the vertex.

    x^2+8x+11

    For standard form I got (x+4)^2=5 but I should have got
    (x-4)^2=-5

    according to the vertex formula:

    -b/2a
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  2. #2
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    Quote Originally Posted by Isimbot View Post
    x^2+8x+11

    For standard form I got (x+4)^2=5 but I should have got
    (x-4)^2=-5 Mr F says: No, see below.

    according to the vertex formula:

    -b/2a
    y = a(x - h)^2 + k has a vertex at x = h. Your vertex formula told you that x = -8/2 = -4 therefore h = -4 which agrees with your earlier (correct) calculation.
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