DS question

[gmatme]

If |a+4| = 2 What is the value of a?
1) a <0
2) a^2 + 8a + 12 =0

Isn't that 1) should be sufficient? a should -6 because it is -ve.

The answer is E?

[Neo2000]

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

[Cybermusings]

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

[800GMAT]

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

[abkhan]

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 .