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shobuj40
 
 

If X not equal to –Y; is X-Y/X+Y>1

by shobuj40 Tue Feb 03, 2009 3:17 pm

If X not equal to -Y; is X-Y/X+Y>1
A. X>0
B. Y<0

Ans: E
shobuj40
 
 

by shobuj40 Tue Feb 03, 2009 3:22 pm

question?

When we can multiply both side of an inequality please explain with example?

Thanks in advance.
RonPurewal
Students
 
Posts: 19744
Joined: Tue Aug 14, 2007 8:23 am
 

Re: If X not equal to –Y; is X-Y/X+Y>1

by RonPurewal Wed Feb 18, 2009 5:54 am

read this, which, coincidentally, is posted on a thread about this very problem.

the rule is simple, actually:
* if you multiply an inequality by a POSITIVE NUMBER on both sides, you change nothing about the inequality sign.
* if you multiply an inequality by a NEGATIVE NUMBER on both sides, you flip the inequality sign (i.e., "<" becomes ">" & vice versa, and "<" becomes ">" & vice versa).

if you don't know the sign of the quantity by which you're multiplying, then you can't do it at all, because of the consequences of these principles: you simply don't know what should happen to the inequality sign.