6

Set 17: Linear Inequalities

Explanation

Answer: A

If x4+2<7\frac{x}{4} + 2 < 7, what is the solution?

A.

x<20x < 20

✓ Correct
B.

x>20x > 20

C.

x<36x < 36

D.

x<9x < 9

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Inequalities with fractions require careful handling but follow familiar patterns. 1. Subtract 2: x4+22<72\frac{x}{4} + 2 - 2 < 7 - 2, giving x4<5\frac{x}{4} < 5 2. Multiply by 4: 4x4<454\cdot \frac{x}{4} < 4 \cdot 5, giving x<20x < 20 3. Check: Try x=16x = 16: 164+2=4+2=6<7\frac{16}{4} + 2 = 4 + 2 = 6 < 7 Strategic Tip: Multiplying both sides by a positive number (like 4) preserves the inequality direction. Choice B is incorrect because it reverses the inequality direction without cause. Choice C is incorrect because it multiplies 7 by 4 first, then adds 8, using incorrect order of operations. Choice D is incorrect because it divides 36 by 4 or uses some other faulty calculation.

Key Steps:

The correct answer is x<20x < 20

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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