Practice GMAT Data Sufficiency Question
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Is (x) a negative number?
 4x^{2} – 8x > (2x)^{2} – 7x
 x + 2 > 0
Correct Answer: A

Evaluate Statement (1) alone.
 Simplify the inequality:
4x^{2} – 8x > (2x)^{2} – 7x
4x^{2} – 8x > 4x^{2} – 7x
8x > 7x
8x + 8x > 7x + 8x
0 > x
x < 0  Since X is less than zero, X is a negative number. This means that negative X is a positive number since multiplying a negative number by a negative number (i.e., 1) results in a positive number.
 Statement (1) alone is SUFFICIENT.
 Simplify the inequality:

Evaluate Statement (2) alone.
 Simplify the inequality:
x + 2 > 0
x >  2  Since we cannot be sure whether X is negative (e.g., 1) or positive (e.g., 2), we cannot be sure whether negative X is positive or negative.
 Statement (2) alone is NOT SUFFICIENT.
 Simplify the inequality:
 Since Statement (1) alone is SUFFICIENT and Statement (2) alone is NOT SUFFICIENT, answer A is correct.
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