Absolute square root

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Source: — Data Sufficiency |

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by cramya » Wed Apr 29, 2009 6:20 pm
Simplify the prob

sqrt(x-5)^2 = |x-5|

When will |x-5| = 5-x only when x<=5

Stmt I

-x |x| >0

|x| is always positive or 0 (cant be 0 since -x*|x|>0)

so x has to be a negative number so - x * positive|x| > 0

Definitely x<=5

SUFF

Stmt II

5 > x or x<5

Again SUFF


D

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by aj5105 » Sat May 02, 2009 5:14 am
Thank You Cramya for the help you are doing to this forum. Highly appreciated!

Had a small question here. Please check the text marked in bold.. Should it not be x<5 as we know for sure |x-5| is negative? (|x-5| = 5-x)


cramya wrote:Simplify the prob

sqrt(x-5)^2 = |x-5|

When will |x-5| = 5-x only when x<=5
Stmt I

-x |x| >0

|x| is always positive or 0 (cant be 0 since -x*|x|>0)

so x has to be a negative number so - x * positive|x| > 0

Definitely x<=5

SUFF

Stmt II

5 > x or x<5

Again SUFF


D