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What is the value of x ? [#permalink]
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23 Jul 2012, 04:43
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Re: What is the value of x ? [#permalink]
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Re: What is the value of x ? [#permalink]
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23 Jul 2012, 05:47
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Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
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Re: What is the value of x ? [#permalink]
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25 Jul 2012, 02:27
Please confirm if this is right logic to prove x<=0? from condition 1: x=x thus, if x>0 ==> x=x ==> 2x=0 ==> x=0 and if x<0 ==> x=(x) ==> x=x...however x<0, then for this condition x will be always less than zero to satisfy x=x Thus in combination x<=0. cyberjadugar wrote: Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards,



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Re: What is the value of x ? [#permalink]
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29 Jul 2012, 06:58
Cyberjadugar/Bunuel, is Pavan puneets approach right to confirm stmt ( 1) leads us to x<=0 ? can you just break stmt 1 down for us a little please ? pavanpuneet wrote: Please confirm if this is right logic to prove x<=0? from condition 1: x=x
thus, if x>0 ==> x=x ==> 2x=0 ==> x=0 and if x<0 ==> x=(x) ==> x=x...however x<0, then for this condition x will be always less than zero to satisfy x=x
Thus in combination x<=0. cyberjadugar wrote: Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards,



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Re: What is the value of x ? [#permalink]
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29 Jul 2012, 07:29
vinay911 wrote: Cyberjadugar/Bunuel, is Pavan puneets approach right to confirm stmt ( 1) leads us to x<=0 ? can you just break stmt 1 down for us a little please ? pavanpuneet wrote: Please confirm if this is right logic to prove x<=0? from condition 1: x=x
thus, if x>0 ==> x=x ==> 2x=0 ==> x=0 and if x<0 ==> x=(x) ==> x=x...however x<0, then for this condition x will be always less than zero to satisfy x=x
Thus in combination x<=0. cyberjadugar wrote: Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards, From (1) we can conclude that \(x\leq{0}\) (check this: whatisthevalueofx136195.html#p1108170), though the approach you are referring to is not precise enough.
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Re: What is the value of x ? [#permalink]
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29 Jul 2012, 07:50
Hi Bunuel, Can you please let me know where I have made the mistake to derive x<=0. It will be really helpful. Thanks.



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29 Jul 2012, 08:10
pavanpuneet wrote: Hi Bunuel, Can you please let me know where I have made the mistake to derive x<=0. It will be really helpful. Thanks. Sure. If we do the way you are proposing then we should consider two cases: If \(x\leq{0}\), then we would have that \(x=(x)\) > \(x=x\), which is obviously true. So, \(x=x\) holds true for any \(x\) which is \(\leq{0}\); If \(x>{0}\), then we would have that \(x=x\) > \(2x=0\) > \(x=0\), which is not a valid solution since we are considering the range when \(x>{0}\). So, if \(x>{0}\) then \(x=x\) has no valid solutions. Therefore, from the above we have that \(x=x\) holds true only when \(x\leq{0}\). Now, you could conclude that right away, since we can rewrite \(x=x\) as \(x=x\), which according to the properties of absolute value is true for \(x\leq{0}\). Hope it's clear.
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Re: What is the value of x ? [#permalink]
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17 Aug 2012, 06:01
I understand the answer explanation, so thanks to everyone who contributed. But what I'm confused is when they use the term "value." Does that always mean they are looking for a single number?



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Re: What is the value of x ? [#permalink]
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16 May 2013, 09:27
Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectWhat is the value of x ? (1) x =  x (2) x^2 = 4 Practice Questions Question: 1 Page: 275 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you! Stmt 1: no value, stmt2: x = 2 or 2 and !x! = 2, so answer i stmt B alone



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Re: What is the value of x ? [#permalink]
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27 Aug 2013, 05:12
Hello, I need help understanding and visualizing the absolute value concept of \(x=x\) For example: \(x=3\) we know that on the number line \(x\) is exactly 3 units away from zero \(x=3\) or \(x=3\) How do we translate \(x=x\)? \(x\) is exactly \(x\) units away from zero? \(x=x\) or \(x=x\)? So when I break statement one down in to further steps I get: \(x=x\) \(+x=x\) or \(x=x\) \(x=x\) or \(x=x\)? I think I am wrong here though? Because how can \(x\leq{0}\)? I would really like to master this concept down. If you have similar questions with \(x=x\) being tested, please post thanks
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Re: DS question from OG [#permalink]
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30 Dec 2013, 12:07
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seabhi wrote: 1. What is the value of x ? (1) x = –x (2) x2 = 4 Posting OG question, did not find in the search. First off, this is a "value" DS question therefore in order to be sufficient, we must be able to calculate a specific value for x S1: x could be a suite of numbers such as: any negative integer or fraction, and 0 > not sufficientS2: 2x = 4  therefore x = 2 > sufficient because we know the value of x, and can now answer the question stem x > 2 = 2 Let me know if this helps!



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Re: What is the value of x ? [#permalink]
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30 May 2014, 11:00
Hi, I've got a big dilemma for this question. For statement 2 x^2=4 I see 3 solution fitting: i) x=2 >> 2^2=4 therefore abs(2)=2 ii) x=(2) >> (2)^2=4 therefore abs(2)=2 BUT iii) sx=qr(4) >>> sqr(4)^2=4. Am I not correct on this? The sterm/question does not say that x has to be an integer right? So sqr(4) can fit in here, isn't it? therefore abs(sqr(4))=sqr(4) Therefore statement 2 is insufficient. Between the OG and Online explanations, I do not understand why sqr(4) could not fit in statement 2. Thx



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27 Sep 2014, 09:10
janani28 wrote: What is the value of x?
(1) x = x (2) x2 = 4 STAT1 x = x => x = x It just tells us that x is a negative number or zero So, INSUFFICIENT STAT2 x^2 = 4 means x = +2 So, x = 2 So, SUFFICIENT So, Answer will be B Hope it helps!
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07 May 2015, 22:52
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A few students above had difficulty in processing the first statement: x = x Here's how you can think through this statement visually: x denotes the distance of an unknown number x from the zero point on the number line. Being the distance, x is always nonnegative. (Please note that it will be wrong to say that the distance x is always positive, because the word 'positive' means 'strictly greater than zero'. It is possible that a point lies ON the zero point, thereby making its distance from the zero point equal to zero. )
So, x = ()(a positive number) = (a negative number) Or, x can be equal to zero (that is, on the number line, point x lies ON the point zero. Therefore, x = distance between 0 and x = 0 as well) The important takeaway is that when processing equations of the type x = x etc., start by first considering that x is nonnegative, since it represents the distance of a number from the zero point on the number line.Hope this helps! Japinder
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Re: What is the value of x ? [#permalink]
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21 Jul 2016, 10:43
Bunuel wrote: What is the value of x ?
(1) x =  x (2) x^2 = 4 We need to determine the absolute value of x. Statement One Alone:x = x If x = x, then x must be negative or 0. For example, if x = 3, 3 = 3. However, since we do not have an exact value for x, statement one is not sufficient. We can eliminate answer choices A and D. Statement Two Alone:x^2 = 4 We can simplify by taking the square root of both sides of the equation: √x^2 = √4 x = 2 Since we have 2 as the value for x, this answers the question. Answer: B
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Re: What is the value of x ? [#permalink]
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29 Aug 2017, 08:26
HI BunuelCan you validate my understanding? (1) x =  x x can be a positive or negative no. (based on x>0 or x<0) but since we do not have an unique value for x, st 1 is insufficient. (2) x^2 = 4 We took square root on LHS and RHS to get x = 2 (2 is not possible on GMAT since square root of negative no shall yield complex no and we deal with only real nos) Since we got an unique answer, st 2 is sufficient
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Re: What is the value of x ? [#permalink]
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29 Aug 2017, 09:21
adkikani wrote: HI BunuelCan you validate my understanding? (1) x =  x x can be a positive or negative no. (based on x>0 or x<0) but since we do not have an unique value for x, st 1 is insufficient. (2) x^2 = 4 We took square root on LHS and RHS to get x = 2 (2 is not possible on GMAT since square root of negative no shall yield complex no and we deal with only real nos) Since we got an unique answer, st 2 is sufficient x is an absolute value of a number, so it CANNOT be negative. x can be positive or 0. When \(x \le 0\) then \(x=x\), or more generally when \(\text{some expression} \le 0\) then \(\text{some expression} = (\text{some expression})\). For example: \(5=5=(5)\); When \(x \ge 0\) then \(x=x\), or more generally when \(\text{some expression} \ge 0\) then \(\text{some expression} = \text{some expression}\). For example: \(5=5\). (1) says that x=x, thus \(x \le 0\). Not sufficient. (2) says that x^2 = 4, so x = 2 or x = 2. I any case x = 2. Sufficient. Check complete solution here: https://gmatclub.com/forum/whatisthe ... l#p110678610. Absolute Value For more check Ultimate GMAT Quantitative Megathread Hope it helps.
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