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og 105 ds

by resilient » Fri Feb 08, 2008 6:14 pm
Is absolute value x = y-z?

1. x=y=z
2. x<0

i dont see how c is the correct answer when I get iconsistent outcomes 1. yes and 1 no when plugging in numbers.. Help please





qa is c
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Re: og 105 ds

by si1ent » Sat Apr 05, 2008 12:16 am
Enginpasa1 wrote:Is absolute value x = y-z?

1. x+y=z
2. x<0

i dont see how c is the correct answer when I get iconsistent outcomes 1. yes and 1 no when plugging in numbers.. Help please





qa is c
for some absolute reason, i can't comprehend this. i feel my IQ dropping.

in my mind, to rephrase the question:

-is the distance of |X| from zero (y-z)?

1) x=z-y
-or-
x= -(-z+y)
-or-
-x=(y-z)


so that tells me positive X's distance from zero is (z-y)
and negative X's distance from zero is (y-z)

now shouldn't the absolute distance of X from zero be the same regardless of whether it's negative or positive?

What am i missing?

thanks!
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Re: og 105 ds

by si1ent » Sat Apr 05, 2008 1:02 am
si1ent wrote:
Enginpasa1 wrote:Is absolute value x = y-z?

1. x+y=z
2. x<0

i dont see how c is the correct answer when I get iconsistent outcomes 1. yes and 1 no when plugging in numbers.. Help please





qa is c
for some absolute reason, i can't comprehend this. i feel my IQ dropping.

in my mind, to rephrase the question:

-is the distance of |X| from zero (y-z)?

1) x=z-y
-or-
x= -(-z+y)
-or-
-x=(y-z)


so that tells me positive X's distance from zero is (z-y)
and negative X's distance from zero is (y-z)

now shouldn't the absolute distance of X from zero be the same regardless of whether it's negative or positive?

What am i missing?

thanks!
quoting myself... |x| = y-z ?

e.g. distance of x is 7 from zero.

y=9
z=2

x is positive, then, 9-2 or x=y-z

x is negative, then -(9-2) or x= -(y-z)

1) x=z-y
x=2-9
x= -7

does this tell me that x is -7, therefore having a distance from zero of 7. since it's negative, then the equation is
|x| = |-(y-z)|.

ok i'm getting sleepy uggh..
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Re: og 105 ds

by Stuart@KaplanGMAT » Sat Apr 05, 2008 8:16 am
Enginpasa1 wrote:Is absolute value x = y-z?

1. x=y=z
2. x<0
Is |x| = y - z?

So, we need to know about x and about y - z.

(1) x = y = z

let's substitute into the original question:

Is |x| = x - x

or

Is |x| = 0?

Well, if x = 0, yes it is. If x = anything else, no it isn't.

We can get a yes and a no: insufficient.

(2) x < 0

So what? Don't know anything about y and z: insufficient.

Combined:

Is |x| = 0?

Well, based on (2) x can no longer equal 0. Every non-0 value for x will give us a "no" answer to the question. So, when we combine we know that |x| is definitely NOT equal to y - z: choose (c).
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Re: og 105 ds

by simplyjat » Sat Apr 05, 2008 9:20 am
Enginpasa1 wrote:Is absolute value x = y-z?

1. x=y=z
2. x<0

i dont see how c is the correct answer when I get iconsistent outcomes 1. yes and 1 no when plugging in numbers.. Help please
qa is c
Please pay more attention while typing the question. The original question reads

1. x+y=z
simplyjat
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hmm

by resilient » Sat Apr 05, 2008 11:22 am
my apologies! x+y=z corrected
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