If xy

Question

If xy < 0, which of the following must be negative ?

A.  xy^2

B.  x^2y

C.  x^2y^2

D.  x^2y^3

E.  x^3y^3

Archit3110 · Answer

given xy < 0
so either of x or y is -ve
from all given options must be -ve would be valid at  x^3y^3 
OPTION E

LipiSinha · Answer

xy<0, so either x or y is less than 0. but which one is positive and which is negative is not known.

The correct answer will be the one which retains the original sign of both x and y. 
Option E is the one which retains the original sign of both x and y, so it must be negative too.

Hence, the answer will be E.

GMATinsight · Answer

xy < 0

i.e. one of x and y is negative and one of positive

Let's check Option with focus on  "MUST be Negative"

A.  xy^2  It will be positive if x is positive and y is negative so OUT

B.  x^2y  It will be positive if y is positive and x is negative so OUT

C.  x^2y^2  It will always be positive

D.  x^2y^3  It will be positive if y is positive and x is negative so OUT

E.  x^3y^3  It will always be Negative

Answer: Option E

Akp880 · Answer

If xy < 0, which of the following must be negative ?

A. xy^2

B. x^2y

C. x^2y^2

D. x^2y^3

E. x^3y^3

Explanation:

Given xy<0
Means x & y are of opposite signs

i.e either x>0,y<0 OR x<0 ,y>0

Checking each option one by one ,Only in option E
(x.y)^3<0
As here too the condition of opposite signs of x& y exists.

Hence E is the correct answer.

Regards
Atul Pandey

Posted from my mobile device

MHIKER · Answer

According to the condition, either x or y is negative.

A. If x is negative then A is the answer, but x could be positive and y could be positive then the value will be positive. So A is out. 
B. X could be negative, the result will be positive. B is out. 
C. the answer will negative if only y is negative but it could positive and then the answer will be positive. So option C is out. 
D. True if y is negative but false if y is negative.
E. For either sign of x and y the result the answer well be negative.

The answer is E.

bumpbot · Answer

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If xy < 0, which of the following must be negative ?

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If xy < 0, which of the following must be negative ?

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