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What is the answer here? Maths! watch

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    [Square root of (x+4)] +2 = x

    Whats the answer? :confused:

    My friend posed this to me today after some test he did
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    Wait . . . nope.

    Duhhh . . . could be a while.
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    Re-arrange so the square root term is the only thing on the left hand side.

    Square both sides.

    Re-arrange and solve the quadratic.

    One of the two solutions will be extraneous so you need to test them both by substitution back in and remove the one that's incorrect.
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    (Original post by Mbob)
    Re-arrange so the square root term is the only thing on the left hand side.

    Square both sides.

    Re-arrange and solve the quadratic.

    One of the two solutions will be extraneous so you need to test them both by substitution back in and remove the one that's incorrect.
    what they said
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    http://www.wolframalpha.com/input/?i...29+%2B+2+%3D+x

    Man use wolfram alpha! Why don't more people use this thing? Just click show steps. It solves all of your mathematical woes!!! (That said when it starts talking about 25/4 I would have just factorised to give x(x-5) = 0 but hey)
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    (x+4)=(x-2)^2

    Expand and you have a lovely quadratic.
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    (Original post by floralia)
    http://www.wolframalpha.com/input/?i...29+%2B+2+%3D+x

    Man use wolfram alpha! Why don't more people use this thing? Just click show steps. It solves all of your mathematical woes!!! (That said when it starts talking about 25/4 I would have just factorised to give x(x-5) = 0 but hey)
    Too bad you can't use wolfram alpha in the exam =P
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    [Square root of (x+4)] +2 = x

    \sqrt {x+4} = x - 2
    (x+4) = x^2 - 4x + 4
    0 = x^2 - 5x + 0
    0 = x(x-5)
     x = 5

    This is bad maths on my behalf as it adds x=0 which is incorrect, however, x=5 is the answer you're looking for!
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    [Square root of (x+4)] +2 = x
    [Square root of (x+4)]= x -2
    x + 4 = x*x - 4x +4
    x*x - 4x +4 - x - 4 = 0
    x*x - 5x = 0
    x*x = 5x
    x = 5
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    Or you could just count from 1 until you find the answer (which is by the time you reach 5). >_>
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    (Original post by nonotrly)
    Or you could just count from 1 until you find the answer (which is by the time you reach 5). >_>
    Unless the answer is 3/2.
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    (Original post by Mbob)
    Unless the answer is 3/2.
    The answer is 5.
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    Holy ****!? what is this awesome ****??
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    (Original post by limetang)
    Too bad you can't use wolfram alpha in the exam =P
    Lol yeah but it does explain how to do stuff in a way which is usually easy to follow.
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    1. Your friend shouldn't be doing maths.
    2. You like Physics - even a Physicist should be able to do that. Solve his problem and don't post a whole thread about it. Serious lack of intelligence.
    3. Wolfram Alpha if both of you are still to thick to solve this pinch problem.
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    No idea what that even means
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    (Original post by floralia)
    Lol yeah but it does explain how to do stuff in a way which is usually easy to follow.
    True, although I've found it not too helpful when using it to integrate things.
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    (Original post by GottaLovePhysics! :))
    [Square root of (x+4)] +2 = x

    Whats the answer? :confused:

    My friend posed this to me today after some test he did

    (Original post by Egor)
    [Square root of (x+4)] +2 = x
    [Square root of (x+4)]= x -2
    x + 4 = x*x - 4x +4
    x*x - 4x +4 - x - 4 = 0
    x*x - 5x = 0
    x*x = 5x
    x = 5
    Therefore, x=5 or x=0....it's a quadratic equation that touches the x-axis at two points.......so it HAS TWO ANSWERS!!!!!!!
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    (Original post by Egor)
    [Square root of (x+4)] +2 = x
    [Square root of (x+4)]= x -2
    x + 4 = x*x - 4x +4
    x*x - 4x +4 - x - 4 = 0
    x*x - 5x = 0
    x*x = 5x
    x = 5
    Ugh, I told him so! You cant just make x+4=-sqrts + x^2
    Thanks for the confirm

    (Original post by SuperiorHuman)
    1. Your friend shouldn't be doing maths.
    2. You like Physics - even a Physicist should be able to do that. Solve his problem and don't post a whole thread about it. Serious lack of intelligence.
    3. Wolfram Alpha if both of you are still to thick to solve this pinch problem.
    He isnt. I did. Its blocked on this internet.
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    (Original post by GottaLovePhysics! :))
    Ugh, I told him so! You cant just make x+4=-sqrts + x^2
    Thanks for the confirm



    He isnt. I did. Its blocked on this internet.
    Looks like you can't speak english either.
 
 
 
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