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Math Help - Solve for x

  1. #1
    MHF Contributor
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    Solve for x

    (3 + x)/(sqrt{3 + x}) = 1

    I found x to be -2.

    The book tells me that the answer is x = -1.

    How can this be?
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  2. #2
    Member arpitagarwal82's Avatar
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    Your answer is correct. Just substitue the value of x in LHS of equation and see it yourself
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  3. #3
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    math books

    Quote Originally Posted by arpitagarwal82 View Post
    Your answer is correct. Just substitue the value of x in LHS of equation and see it yourself
    I knew that I was right. I find that math books have a lot of wrongs answers in the answer section.
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  4. #4
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by magentarita View Post
    (3 + x)/(sqrt{3 + x}) = 1

    ]I found x to be -2.

    The book tells me that the answer is x = -1.

    How can this be?
    (3+x) = \sqrt{3+x}

    square both sides:

    x^2 + 6x + 9 = 3+x

    x^2 + 5x +6 = 0
    <br />
(x+3)(x+2) = 0

    therefore both -3 and -2 are solutions
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  5. #5
    Rhymes with Orange Chris L T521's Avatar
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    Quote Originally Posted by e^(i*pi) View Post
    (3+x) = \sqrt{3+x}

    square both sides:

    x^2 + 6x + 9 = 3+x

    x^2 + 5x +6 = 0
    <br />
(x+3)(x+2) = 0

    therefore both -3 and -2 are solutions


    If you plug -3 back into the original equation \frac{3+x}{\sqrt{3+x}}=1, you have \frac{0}{0}=1 which is impossible, since \frac{0}{0} is an indeterminate value... XD

    So magentarita's answer x=-2 is the only solution.
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  6. #6
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    Yes...

    The only answer that makes sense is x = -2. If we replace x with -3, we create division by zero, which is undefined.
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