ds w/ absolute value

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ds w/ absolute value

by vasilisab » Sun Sep 23, 2007 11:39 am
What is the value of y?

(1) 3|x2 – 4| = y – 2

(2) |3 – y| = 11

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by nkumar » Mon Sep 24, 2007 3:10 am
1 is ruled out at it includes another variable
2. there are two scenarios a. when (3-y)>0 and b. when (3-y) < 0
a. 3-y =11 => y= -8
b. -(3-y)= 11 => y=14
so, two different values of y
The answer should be E
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by gmatguy16 » Mon Sep 24, 2007 9:57 am
but when you combine 1 and 2 you realize that y cannot be negative,it has to be positive..so only only value for y .answer should be c

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by [email protected] » Mon Sep 24, 2007 12:40 pm
Option 1 gives you the condition :
y - 2 > 0 or y > 2
Option 2 gives two answers
-8 and 14.

Combining both we get 14.
Hence C

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by nkumar » Mon Sep 24, 2007 1:57 pm
gmatguy16 wrote:but when you combine 1 and 2 you realize that y cannot be negative,it has to be positive..so only only value for y .answer should be c
But mod (x2-4) can be negative when x2 is less than 4 for example when x is =0 or 1, x2-4 may have negative values as well, isn't it??

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by kajcha » Mon Sep 24, 2007 7:06 pm
|x^2-4| will always be positive...

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by mallard906 » Tue Sep 25, 2007 11:39 am
Also agree w/ C. Abs values are always positive...