Find the sum of 32 terms of an A.P. whose third term is 1 and the 6th

1.	Find the sum of 32 terms of an A.P. whose third term is 1 and the 6th term is -11.
Answer» Third term =a+2d=1---(¡) and sixth term = a+5d=-11 ---(¡¡) subtract equation (¡)from(¡¡) we get d=-4 then put the value of d in equation I we get a = 9 then sum = n÷2×[2a+(n-1)×d] we get sum is -1696 Answer= -1696

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