Find the sum of first 25 terms of an A.P. whose nth term is given by 
.
Given, nth term, an = 2 – 3n
Put n = 1, a1 = 2 – 3(1) = -1
Put n = 25, a15= 2 – 3(15) = -43
Therefore, S25 = 
(-1 – 43)
= 
(-44) = -925
26
Find the sum of first 25 terms of an A.P. whose nth term is given by .
Given, nth term, an = 2 – 3n
Put n = 1, a1 = 2 – 3(1) = -1
Put n = 25, a15= 2 – 3(15) = -43
Therefore, S25 = (-1 – 43)
= (-44) = -925