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GMAT Prep Question √x^2/x = ?

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rohinivt
 Post subject: GMAT Prep Question √x^2/x = ?
 Post Posted: Mon Dec 06, 2010 10:23 pm 
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Students


Posts: 3
Hi All,
This particular question must have discussed in this forum. But couldn't locate the link.
I got the following question from GMAT Prep.
If x =/ 0, √(x^2)/x =

{=/ means "not equal to"}

A) -1
B) 0
C) 1
D) x
E) |x|/x

I marked C. But the Official Answer is:E
I chose C because, I thought that whatever inside the "√" sign is +ve. So √(x^2) is always +ve x and so the answer is C.

In one of Ron's comments, http://www.manhattangmat.com/forums/posting.php?mode=quote&f=30&p=21193
Ron said "when you have an OPERATOR SYMBOL, such as "√", that symbol will produce exactly ONE value.
for instance, √9 is just 3."

Usually GMAT cannot be wrong. So what is wrong with my logic?
Thanks in Advance.
R
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tim
 Post subject: Re: GMAT Prep Question √x^2/x = ?
 Post Posted: Tue Dec 07, 2010 10:31 am 
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ManhattanGMAT Staff


Posts: 2242
Location: Southwest Airlines, seat 21C
x could be negative. In that case you would have a positive divided by a negative, which is never equal to 1. The thing to remember here is that root(x^2) is identically equal to |x|; keep that in mind, because it shows up from time to time..

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Tim Sanders
Manhattan GMAT Instructor
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