10

Set 2: Linear Equations

Explanation

Answer: B

If 7x−2x=307x - 2x = 30, what is the value of xx?

A.

15

B.

6

✓ Correct
C.

5

D.

3.33

Detailed Explanation

Choice B is correct. Choice A is the correct answer. 1. Start with the equation: 7x−2x=307x - 2 x = 30 2. Combine like terms: 5x=305x = 30 3. Divide by 5: x=6x = 6 4. Verify: 7(6)−2(6)=42−12=307(6) - 2(6) = 42 - 12 = 30 ✓ Choice C is incorrect because this results from dividing by 2: 30/2=1530 /2 = 15. Choice C is incorrect because this results from dividing by 9 (adding terms instead of subtracting): 30/9≈3.3330 /9 \approx 3.33. Choice D is incorrect because this results from calculation error.

Key Steps:

•

The correct answer is 6

Why others are wrong:
A: Choice A 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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