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value of x?

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value of x?

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What is the value of x?

(1) X^2 - 4 = 0
(2) X satisfies the equation y^2 = x where y is real

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ritula wrote:
What is the value of x?

(1) X^2 - 4 = 0
(2) X satisfies the equation y^2 = x where y is real
(1) x could be +/-2, so insufficient

(2) if y is a real number, then y^2 must be greater than or equal to 0, which means that x is greater than or equal to 0. That's a lot of possible values: insufficient.

Together, statement (2) means that x can no longer be negative, so the only value of x that satisfies both rules is +2: choose (c), together sufficient.

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