2

Set 8: Linear Inequalities

Explanation

Answer: A

If 0.5x1.20.3x+0.85x - 1.2 \leq 0.3x + 0.8, what is the solution?

A.

x10x \leq 10

✓ Correct
B.

x10x \geq 10

C.

x4x \leq 4

D.

x4x \geq 4

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Decimals in inequalities work the same as whole numbers. 1. Subtract 0.3 x: 0.5x0.3x1.20.3x0.3x+0.80.5x - 0.3 x - 1.2 \leq 0.3 x - 0.3 x + 0.8, giving 0.2x1.20.80.2x - 1.2 \leq 0.8 2. Add 1.2: 0.2x2.00.2x \leq 2.0 3. Divide by 0.2: x10x \leq 10 Strategic Tip: You can multiply all terms by 10 to eliminate decimals: 5x123x+85x - 12 \leq 3 x + 8, then solve normally. Choice B is incorrect because it reverses the inequality direction. Choice C is incorrect because it might come from dividing 0.8 by 0.2 without adding 1.2 first. Choice D is incorrect because it combines wrong value with wrong direction.

Key Steps:

The correct answer is x10x \leq 10

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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