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What is the value of |x|?

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What is the value of |x|?

by Vincen » Tue Dec 12, 2017 10:34 am
What is the value of |x|?

(1) x = -|x|

(2) x^2 = 4

The OA is B.

I don't understand why the statement (2) is sufficient. Experts, can you give me an explanation here?

I think the correct option is C.
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Source: — Data Sufficiency |

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by [email protected] » Tue Dec 12, 2017 2:25 pm
Hi Vincen,

We're asked for the value of |X|. This question can be solved with a mix of basic math, TESTing VALUES and Number Property rules. It's worth noting that the |X| will always either be positive or 0.

1) X = -|X|

With the information in Fact 1, we know that X CANNOT be positive. X can be 0 or any negative value.
IF...
X = 0, then the answer to the question is |0| = 0
X = -1, then the answer to the question is |-1| = +1
Fact 1 is INSUFFICIENT.

2) X^2 = 4

The equation in Fact 2 has 2 solutions: +2 ad -2
X = +2, then the answer to the question is |+2| = +2
X = -2, then the answer to the question is |-2| = +2
The answer to the question is ALWAYS +2
Fact 2 is SUFFICIENT.

Final Answer: B

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