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10 Jan 2015, 17:07
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I have a question that involves taking the roots of a number.
\(\sqrt{64}\) = 8
However, why can't it equal -8. For example:
x = \(\sqrt{64}\)
(x)^2 = \(\sqrt{64}\)^2
\(x^2-64=0\)
\((x-8)(x+8)=0\)
\(x= +/-8\)
Thanks in advance for your help!
\(\sqrt{64}\) = 8
However, why can't it equal -8. For example:
x = \(\sqrt{64}\)
(x)^2 = \(\sqrt{64}\)^2
\(x^2-64=0\)
\((x-8)(x+8)=0\)
\(x= +/-8\)
Thanks in advance for your help!
10 Jan 2015, 19:48
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Hi bionication,
These are just the accepted conventions behind the math.
Square roots have JUST 1 solution - a POSITIVE one
Squares have 2 solutions - 1 positive AND 1 negative
**The exception to both of these rules is 0 - the square root of 0 is 0 and X^2 = 0 has just one solution.....X=0).
When these math symbols show up in a Quant question, it's important to pay attention to what you were GIVEN. That initial information dictates what the correct answer is (or could be).
GMAT assassins aren't born, they're made,
Rich
These are just the accepted conventions behind the math.
Square roots have JUST 1 solution - a POSITIVE one
Squares have 2 solutions - 1 positive AND 1 negative
**The exception to both of these rules is 0 - the square root of 0 is 0 and X^2 = 0 has just one solution.....X=0).
When these math symbols show up in a Quant question, it's important to pay attention to what you were GIVEN. That initial information dictates what the correct answer is (or could be).
GMAT assassins aren't born, they're made,
Rich
10 Jan 2015, 20:18
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Appreciate the response, Rich.
