Pls reply..confused in such a silly looking question..?

+ or - 3 square is equal to 9. all know. but, ROOT of 9 is equal to + or - 3? Or just + 3? And how?

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  • Anonymous
    1 decade ago
    Favorite Answer

    arey yar very simple ?

    if u get answer for this ? from someone else pls forward it to me.

  • 1 decade ago

    When you are finding a square root there will always be two answers, the (+) answer and the (-) answer. That's because when you multiply two (-) numbers together they make a (+) answer. So the square root of 9 will be (+) or (-) 3. Check:

    when you multiply +3 x +3 you get 9

    when you multiply -3 x -3 you get 9

    If this is just a math problem you would report both answers. If this were the answer to a practical problem the negative root may have no meaning. For example when asked to find the length of something it would not make sense to have a negative number which would mean "less than none" and so you wouldn't use the negative root.

  • 1 decade ago

    The definition of a square root is

    √x is a number which, when multiplied by itself equals x, therefore

    √9=+/-3 since (-3)^2=9 & (3)^2=9

  • 1 decade ago

    It is a matter of definition of terms.

    Square root of a non-negative number is defind to be that non-negative number which when squared yields the first number.

    Both 3 & -3 yield 9 when squared, but according to the definition, only 3 is said to be the square root of 9, just by convention.

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  • 1 decade ago

    square root of 9 = +3 and -3

    However the square root sign is defined to return only the absolute value of the root. So in that case sqrt(9) = 3

  • 1 decade ago

    Yes.

    x^2 = 9 has two solutions.

    x = -3 and x = + 3.

    But when mathmeticians invented the square root function, they

    considered it best if it have only one value instead of two.

    so, they declared that square root to be, by definition, a positive number.

    As a consequence, when ever we solve a quadratic,

    x^2 = 9,

    we must say

    x = plus or minus square root of 9.

    In some of the more advanced math theories, it turns out

    to be more convenient to let square root have two values.

    But for simple algebra, it is indeed simpler to define square root to have only one value.

  • 1 decade ago

    Root of 9 has two values one is +3 and the other is - 3.

    Root of any number has two values one is positive and the other is negaitive.

    Don't forget to put +or- sign ( both the signs)in front of the number found.

    It is because (+3 ) x (+3) =( + 9)

    Also (-3 ) x (-3) = (+ 9)

  • 1 decade ago

    +3x+3 = +9 therefore +3 squared is +9

    The square root of +9 is +3 cause +3x+3 = +9

  • 1 decade ago

    Once I figured out what you were asking, I knew the answer. The answer is... both. It can be either, but usually people ignore this and assume that the negative root is irrelevant. On some problems, however, it can be either way and you have to work out both.

  • 1 decade ago

    actually you see it depends on the problems.

    but sqrt of 9 is + or - 3 but it changes according to questions.

    Source(s): mind
  • 1 decade ago

    It can be either positive or negative 3

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