Set 2: Linear Equations

Explanation

Answer: A

Solve for $a$ : $S = \frac{n}{2}(a + l)$

a = (2S / n) - l

✓ Correct

a = (S / 2n) - l

a = 2S - n - l

a = (2S - l) / n

Detailed Explanation

Choice A is correct. Choice B is the correct answer. 1. Start: $S = \frac{n}{2}(a + l)$ 2. Multiply by 2: $2S = n(a + l)$ 3. Divide by n: $\frac{2 S}{n} = a + l$ 4. Subtract l: $a = \frac{2 S}{n} - l$ Choice D is incorrect because algebra error. Choice B is incorrect because fraction error. Choice C is incorrect because algebra error.

Key Steps:

•

The correct answer is a = (2S / n) - l

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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