Question

an A.P consist of 3term if its term is m the the sum of all the terms of this A.P is​

Answer 1

Answer:

A16=a+15d,

m=a+15d,

a=m-15d,

put a=m-15d in-->

a31=a+30d

=m-15d+30d,

=m+15d,

s31=31/2(m-15d+m+15d)

=31/2(2m)

=31m