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Math Expert
Joined: 02 Sep 2009
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15 Sep 2014, 23:11



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26 Nov 2014, 05:27
Hi all I thought that when you took the square root of a perfect square you only needed to consider the positive answer for GMAT questions so in this case the answer would be B. Could someone please clarify Thank you in advance
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26 Nov 2014, 06:14
alexjordan99 wrote: Hi all I thought that when you took the square root of a perfect square you only needed to consider the positive answer for GMAT questions so in this case the answer would be B. Could someone please clarify Thank you in advance
Posted from my mobile device When the GMAT provides the square root sign for an even root, such as a square root, fourth root, etc. then the only accepted answer is the positive root. That is: \(\sqrt{9} = 3\), NOT +3 or 3; \(\sqrt[4]{16} = 2\), NOT +2 or 2; Notice that in contrast, the equation \(x^2 = 9\) has TWO solutions, +3 and 3. Because \(x^2 = 9\) means that \(x =\sqrt{9}=3\) or \(x=\sqrt{9}=3\).
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27 Nov 2014, 07:49
Thank you very much !
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02 Dec 2014, 23:17
Don't we have negative primes?



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29 Jun 2015, 00:00
(1) x=2 => x =+2 or x=2.. NS
(2) x^2 = 4 = > x = 2 => x =+2 or x = 2 NS
On combining both mean the same.. Hence Not Sufficient.. Answer is E..



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14 May 2017, 01:24
In the above discussion it is said that we cannot have the negative prime so we will have only +2 as the answer and hence the answer should be d. please explain...



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14 May 2017, 01:31



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15 Sep 2018, 15:51
Hi, sorry if this is a dumb question, but I thought the x signaled "absolute value" of a number? So even if you had a negative number it would still be a positive? 2 spots away from zero? So if x=2 then it would be enough information to answer whether x was a prime number? Does my question make sense?



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16 Sep 2018, 00:16










