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Math Help - Solving a square equation?

  1. #1
    Newbie Bluerabbits's Avatar
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    Exclamation Solving a square equation? SOLVED

    Hi!

    Im doing maths at the moment and Im having trouble solving the following question:

    4 (x+7)^2 = 36

    I started of by just taking the root of both
    so it became:

    2 ( x + 7) = 6


    And now I dont know what to do, Im trying to solve this by the help of the quadratic formula.
    Last edited by Bluerabbits; March 15th 2011 at 01:54 PM. Reason: SOLVED
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  2. #2
    Super Member Quacky's Avatar
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    Careful! Remember that (6)^2=(-6)^2=36, so \sqrt{36}=\pm 6

    Once you change your method to incorporate the two possible solutions, your method would work However, I would just have divided both sides of the equation by 4 at the beginning:

    (x+7)^2=9

    Now take the square root of both sides, but remember that you should obtain two solutions as \sqrt{9}=\pm{3}

    You could choose to do this using the quadratic formula, but it would be unnecessary; you'd have to expand the brackets and then rearrange terms - this approach is far simpler!
    Last edited by Quacky; March 15th 2011 at 01:57 PM.
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  3. #3
    Newbie Bluerabbits's Avatar
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    Hi! Thank you both for the great explainations!
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