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DS question

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Source: — Data Sufficiency |

by Neo2000 » Thu May 17, 2007 7:57 am
Mod implies it can be either +(a+4) or -(a+4)

If +(a+4) = 2
a = -2

If -(a+4) = 2
-a - 4 = 2
-a = 2+4 => a = -6
Thus you cannot get an answer from 1

From two you again get (a+6)(a+2) = 0
Again you get a = -6 or -2

Combining both you dont get anything new

Hence E
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by Cybermusings » Fri May 18, 2007 5:58 am
If |a+4| = 2 What is the value of a?
1) a <0
2) a^2 + 8a + 12 =0

Statement I : Insufficient since a can be -2 and -6 and in both cases the value of the equation will be 2

Statement II : Quadratic equation when solved gives us (a+2)(a+6) = 0
Hence a = -2 or a=-6
Insufficient

Statement I and II:Value of a can be -2 or -6. hence E
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by 800GMAT » Sat May 19, 2007 6:28 pm
Question Stem|a+4| = 2
upon squaring both sides you get:
a^2 + 8a + 12 =0
and you get two values of a : a= -2 and a= -6

stmt 1 states a<0. but this does not let us eliminate either values
hence insuff

Stmt 2 is just the question stem restated...insuff


Stmts 1 and 2 still dont give enough info to accept one value and eliminate the other

hence E
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by abkhan » Sun May 20, 2007 2:05 am
As said above it is important to see that it is the equation which is inside the mod value |a+4| not just a. This changes the question .
I am ..therefore I am..
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