8

Set 12: Linear Equations (Advanced)

Explanation

Answer: C

The side of a square is 3x23x - 2. If the perimeter is 40, what is xx?

A.

3

B.

10

C.

4

✓ Correct
D.

12

Detailed Explanation

Choice C is correct. Choice A is the correct answer. 1. Perimeter Formula: P=4sP = 4 s 2. Substitute: 40=4(3x2)40= 4(3 x - 2) 3. Divide by 4: 10=3x210= 3 x - 2 4. Add 2: 12=3x12= 3 x 5. Divide by 3: 4=x4= x 6. Verify: Side is 1010. 4(10)=404(10) = 40 ✓ Choice B is incorrect because it results from an error in the solution process. Choice D is incorrect because it results from an error in the solution process. Choice C is incorrect because it results from an error in the solution process.

Key Steps:

The correct answer is 4

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