The first , second and the last terms of an A.P. are `a ,b , c` respectively. Prove that the sum is `((a+c)(b+c-2a))/(2(b-a))` .

Explanation

To prove that the sum of the first, second, and last terms of an A.P. (Arithmetic Progression) is given by the formula \(\frac{(a+c)(b+c-2a)}{2(b-a)}\), we will follow these steps:

### Step 1: Identify the terms
Given:
- First term \(a\)
- Second term \(b\)
- Last term \(c\)

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