2

Set 5: Linear Inequalities (Advanced)

Explanation

Answer: A

Solve: 1x>2\frac{1}{x} > 2 (Non-linear preview)

A.

0<x<0.50 < x < 0.5

✓ Correct
B.

x>0.5x > 0.5

C.

x<0.5x < 0.5

D.

x>2x > 2

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Be careful multiplying by xx (sign change if negative). 1. Case 1 (x>0x > 0): Multiply by xx: 1>2x0.5>x1> 2 x \rightarrow 0.5 > x. Combined with x>0x>0: 0<x<0.50< x < 0.5. 2. Case 2 (x<0x < 0): Multiply by xx (reverse sign): 1<2x0.5<x1< 2 x \rightarrow 0.5 < x. But xx must be negative, so no solution here (0.5<x<00.5< x < 0 is impossible). 3. Result: 0<x<0.50< x < 0.5 Strategic Tip: For rational inequalities, consider the sign of the denominator. Or test points: x=0.110>2x=0.1 \rightarrow 10 > 2 (True). x=11>2x=1 \rightarrow 1 > 2 (False). Choice B is incorrect. Choice C is incorrect because it includes negative numbers. Choice D is incorrect.

Key Steps:

The correct answer is 0<x<0.50< x < 0.5

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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