Practice GMAT Data Sufficiency Question

Is (-x) a negative number?

A)	Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B)	Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C)	BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D)	EACH statement ALONE is sufficient.
E)	Statement (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data are needed.

Correct Answer: A

Evaluate Statement (1) alone.
1. Simplify the inequality:
  4x² – 8x > (2x)² – 7x
  4x² – 8x > 4x² – 7x
  -8x > -7x
  -8x + 8x > -7x + 8x
  0 > x
  x < 0
2. 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.
3. Statement (1) alone is SUFFICIENT.
Evaluate Statement (2) alone.
1. Simplify the inequality:
  x + 2 > 0
  x > - 2
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.
3. Statement (2) alone is NOT SUFFICIENT.
Since Statement (1) alone is SUFFICIENT and Statement (2) alone is NOT SUFFICIENT, answer A is correct.