Question

plz................. solve it..................

Answer 1

First term =a
second term =b
last term =c
common difference=(b-a)
tn =a+(n-1) d

c=a+(n-1) d

(c-a)=(n-1)(b-a)

(c-a)/(b-a)+1=n

( c+b-2a)/(b-a)=n--------------------(1)
now ,
we know sum of n terms=n/2 (first term+last term)
put equation (1)value
= (b+c-2a)/(b-a)(a+c)
hence Sn=[(b+c-2a)(c+a)/(b-a)]

Read more on Brainly.in - https://brainly.in/question/1086454#readmore