![]() |
| if y is greater than or equal to 0, |
| Re: if y is greater than or equal to 0, |
|
Ron Purewal
MGMAT STAFF
|
they're being tricky little #$@^&*'s here.
but first, i must address this:
no no no! no! and by the way, no! the expression in question is an ABSOLUTE VALUE, |x - 3|. two things about this expression: (1) you ABSOLUTELY CANNOT remove the absolute value bars and replace all the minus signs with plus signs (i.e., produce x + 3). this will always, always, ALWAYS be wrong. if you don't see what's so wrong about this, then compare |10 - 3| and 10 + 3; that ought to get the idea across. remember, any statement that's false for numbers is also false for variables, because variables stand for numbers. (2) what it IS equivalent to is either (x - 3), if x - 3 is nonnegative (i.e., if x > 3), or (-x + 3), the opposite of the expression within the bars, if x - 3 is negative (i.e., if x < 3). if you don't know the value of x, there is no way to remove the absolute value bars, so don't try. instead... think about the number properties associated with absolute values. in particular, the most important property of absolute values - which, fortunately, is also one of their simplest and most easily understood - is this: absolute values can't be negative. this observation alone is actually enough to solve this problem. here's how: (1): all this tells you is that |x - 3|, an absolute value, is at least some positive number. this isn't much of a restriction, as it could be anything greater than that number, so there's no way you'll get a unique value for x. insufficient. (2): (-y) is 0 or less, and the absolute value must be at or below this value. combined with the basic observation that appears in boldface above, this tells you that y must be 0, and that the absolute value itself must also be 0. (think about the other possibilities for (-y) if this doesn't make sense to you right away). therefore, |x - 3| = 0, so x must be 3. sufficient! |
||||||||||||||
|
|
|||||||||||||||
| thanks |
|
guest612
Guest
|
thanks, ron, for your responses, which have been really great! i took the exam tonight! i improved on quant but choked on verbal which is usually my forte. will have to take it again. but thanks again for all your help! i read through your replies last night and it helped my confidence in quant which i think made a difference.
|
||||||||||||
|
|
|||||||||||||
| Re: thanks |
|
Ron Purewal
MGMAT STAFF
|
glad i could help. hope you can lay it down on verbal if you decide to retake the exam. good luck with applications, etc |
||||||||||||||
|
|
|||||||||||||||
| if y is greater than or equal to 0, |
|
||
|
Powered by phpBB © phpBB Group
Content © Manhattan GMAT Forums
*GMAT and GMAT CAT are registered trademarks of the Graduate Management Admission Council,
which neither sponsors nor endorses this test preparation service.
Content © Manhattan GMAT Forums
*GMAT and GMAT CAT are registered trademarks of the Graduate Management Admission Council,
which neither sponsors nor endorses this test preparation service.

