college algebra--need help Please!!!

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I need to find the vertex and axis of symmetry of the folowing quadratic function. Can someone PLEASE help me!!

y= -x^2-6x

  • college algebra--need help Please!!! -

    You can complete the square ....

    y = -(x^2 + 6x +9 - 9
    = -( (x+3)^2 - 9)
    = -(x+3)^2 + 9

    vertex is (-3, 9)

    alternate method:

    for y = ax^2 + bx + c
    the x of the vertex is -b/2a
    for for yours
    the x of the vertex is -(-6)/-2 = -3
    sub into the function ...
    y = -9 + 18 = 9
    so the vertex is (-3,9) as above

    The simplest way is to use Calculus, but I am not sure if you are studying Calculus.

  • college algebra--need help Please!!! -

    Reiny,

    It seems like Calculus, but it actually falls under college algebra. Because I can get some calculus tutoring and the answers fit. Thank you for the help, it is greatlt appreciated!!!

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