BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Absolute Value question

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Wed Sep 03, 2008 7:15 am

Absolute Value question

by maia » Fri Sep 19, 2008 10:30 am
In OG 11 absolute value |x| is defined as distance between number x and 0 on the line number so |-3| = 3 and |3| = 3.

It is also defined as |x| = x if x >=0 and |x| = -x if x < 0 . So |-3| = -3 and |3| = 3 ??

Math gurus, What is correct?

Thanks
Maia
Top
Source: — Quantitative Reasoning |
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Tue Aug 26, 2008 1:09 am
Thanked: 2 times

by chayanika » Fri Sep 19, 2008 11:58 am
Modulus of any number is always positive because it is the absolute size of the number. That is we disregard any sign it might have. That makes |x|=x and |-x| = x. Similarly |3|=3 and |-3| = 3

But to get the modulus of a negative number we need to multiply the number by -1, for example -1*(-3 )

Hence we can generalise the above finding by saying that to get modulus of positive number (x) we can directly write x while to get the modulus of a negative number we need to multiply by -1*x = -x

Therefore, |x| = {x, if x is positive and -x if x is negative}
Top
Post new topic Post Reply
• Page 1 of 1