x^4+x^2+1/x^2 -4x-5>0
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GMAT Club Forum Index Data Sufficiency (DS)
What is the value of x? (1) x^4 + x^2 + 1 =1/(x^4 + x^2 + 1) (2) x^3 : Data Sufficiency (DS)
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gmatt1476
Sep 21, 2019
00:00 ABCDE
DIFFICULTY: (N/A) QUESTION STATS: based on 431 sessions
61% (01:30) correct
39% (01:51) wrong
What is the value of x?
(1)
(2)
DS64402.01
Spoiler: OA
Kudos
3 kudos, 11 bookmarks
Most Helpful Community Reply
Karmesh
Sep 30, 2019
gmatt1476 wrote:
What is the value of x?
1. Take the denominator to the other side and we have ( x^4 + x^2 + 1 )^2 =1
When will LHS be equal to 1? before looking any further just give it a thought.
.
x^4 and x^2 are both +ve, so the only case possible is when x=0.
S1 SUFF
2. x^3 can be -ve, so apart from 0 you can also have x=-1. This gives us 2 values.
INSUFF