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answers:
RAT M say: 22
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Tatiana say: 9
Since 9 times 9 is 81. Then the answer is 9.😋
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Tyler say: 9
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Jim Moor say: Since -9*-9 = 81, -9 is a root
Since 9*9 =81, 9 is a root
√81 = ± 9
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bubba say: A German would not agree with this question
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Como say: + ve square root is 9
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MICHAEL K say: 9.
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D.W. say: √81 = 9
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JosephV say: 09
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Raymond say: A square root is a value which, when multiplied by itself, gives you the answer.
For 81, you are looking for a value which, when multiplied by itself, gives a product of 81.
I know of two such values.
The first one is 9
because 9 * 9 = 81
The second one is -9
because (-9) * (-9) is also equal to 81
To distinguish between the two, we call the positive one (+9) the "principal square root".
In higher mathematics, unless the question specifically asks for the other one, we always use ONLY the principal square root.
However, in real life and in algebra, there are cases where BOTH answers can be correct.
For example, if you are asked to find the value of x when solving this problem:
x^2 - 81 = 0
then both of them (one at a time) are correct.
x^2 - 81 = 0
works when x = 9
and it also works when x = -9.
Also, if "x=0" represents the centre of the bridge, and you are asked what position of a truck would put the maximum strain on a particular cable (and the tension in the cable is represented by some equation), then it is possible that there are two answers, one is 9 metres before reaching centre, and the other is 9 metres after passing centre.
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Whites killed Harambe say: 8+1 = 9
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Unknown say: sqrt(81)
= sqrt(9 * 9)
= 3 x 3
= 9
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Paul say: The square root function only returns the positive (principle) root. So the answer is 9.
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