Absolute Value basics

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revoltangel: Junior | Next Rank: 30 Posts; Posts: 23; Joined: Wed Oct 15, 2008 10:11 am; Location: california

Absolute Value basics

by revoltangel » Sun Dec 28, 2008 1:26 pm

I need help knowing the basic rule of absolute values. I've always been taught that anything inside the " | x | " absolute value sign always comes out positive. I am learning that is not always the case. What should I know about absolute value when it comes to the GMAT? Thx

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Source: Beat The GMAT — Quantitative Reasoning | Sun Dec 28, 2008 1:26 pm

cramya: Legendary Member; Posts: 2467; Joined: Thu Aug 28, 2008 6:14 pm; Thanked: 331 times; Followed by:11 members

by cramya » Sun Dec 28, 2008 1:39 pm

Revolt,

|x| is never negative

By defnition:

If x is positive or 0 then |x| = x

If x is neagtive then |x| = -x (negative(negative) = positive here x is negative)

Eg:

Let x=-2

|x| = |-2| by defnition = - x = - (- 2) = 2

I am learning that is not always the case

Can u help me understand what u meant above just so we are on the same page?

Last edited by cramya on Sun Dec 28, 2008 9:14 pm, edited 1 time in total.

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