Show that the sum of an A.P. whose first term is a, the second term is b and the last term is c, is equal to `((a+c)(b+c−2a))/(2(b−a))

Explanation

To show that the sum of an arithmetic progression (A.P.) whose first term is \( a \), second term is \( b \), and last term is \( c \) is equal to

\[ \frac{(a+c)(b+c-2a)}{2(b-a)}, \]

we will follow these steps:

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