Question

Difficulty: MediumQuestion Stem Simplification and Target Rephrasing

For all real numbers xx such that x0x \neq 0 and x1x \neq 1, the Data Sufficiency Yes/No target question "Is x2xx1>0\frac{x^2 - x}{|x - 1|} > 0?" is algebraically equivalent to asking "Is x>0x > 0?".

Answer: Answer

Answer

The statement is False.
The statement is False because simplifying the target inequality x(x1)x1>0\frac{x(x - 1)}{|x - 1|} > 0 yields x<0x < 0 or x>1x > 1, which is not equivalent to x>0x > 0.

Step-by-Step Solution

1
Factor the numerator of the expression in the target inequality.
x2xx1=x(x1)x1\frac{x^2 - x}{|x - 1|} = \frac{x(x - 1)}{|x - 1|}.
Factoring allows for analyzing the individual signs of the linear factors.
2
Analyze the denominator to simplify the inequality.
Since x1>0|x - 1| > 0 for all x1x \neq 1, multiplying both sides of x(x1)x1>0\frac{x(x - 1)}{|x - 1|} > 0 by x1|x - 1| gives the equivalent inequality x(x1)>0x(x - 1) > 0.
Multiplying an inequality by a strictly positive quantity preserves the direction of the inequality sign.
3
Solve the quadratic inequality x(x1)>0x(x - 1) > 0.
The product x(x1)x(x - 1) is positive when both factors have the same sign, yielding the solution set x<0x < 0 or x>1x > 1.
A product of two real terms is positive when both terms are positive or both terms are negative.
4
Compare the rephrased target (x<0x < 0 or x>1x > 1) with the proposed target (x>0x > 0).
The range 0<x<10 < x < 1 makes x>0x > 0 true but makes x(x1)>0x(x - 1) > 0 false. Thus, the targets are not equivalent.
Two target questions are algebraically equivalent if and only if they yield identical truth values for all values in the domain.

Key Concept

Question Stem Simplification and Target Rephrasing
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