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

Redeem

Root Expressions

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Senior | Next Rank: 100 Posts
Posts: 56
Joined: Wed Sep 01, 2010 10:04 am
Thanked: 1 times
Followed by:20 members

Root Expressions

by Akansha » Sun May 29, 2011 10:36 am
x < 0, then √-x |x| (root of the whole expression)
a. -x
b. -1
c. 1
d. X
e. √x

OA is A. I got the answer as D. Can someone tell why is it not so? [/spoiler]
Top
Source: — Problem Solving |
Legendary Member
Posts: 544
Joined: Mon Dec 27, 2010 8:10 am
Thanked: 45 times
Followed by:2 members

by sameerballani » Sun May 29, 2011 10:44 am
Akansha wrote:x < 0, then √-x |x| (root of the whole expression)
a. -x
b. -1
c. 1
d. X
e. √x

OA is [spoiler]A. I got the answer as D. Can someone tell why is it not so? [/spoiler]
Assume x = -4 (x<0)
Root[-x|x|]= Root[-(-4|-4|)]= Root[-(-4)*4]= Root[4*4]= 4 = -(-4)= -x = option A
Top
User avatar
Legendary Member
Posts: 1309
Joined: Mon Apr 04, 2011 5:34 am
Location: India
Thanked: 310 times
Followed by:123 members
GMAT Score:750

by cans » Sun May 29, 2011 1:46 pm
√-x |x| (root of the whole expression) should be +ve as there is no '-' sign in front of root.
and we know x<0
Thus D is not the answer.
and -X>0, also √-x |x| = |x|
Thus A is the answer.
Top
Post new topic Post Reply
• Page 1 of 1