Question

Find the sum ot n term of an



a.p whose nth term is 5+6n,n belongs to n

Answer 1

ap is 11,17,23....
a=11
d=6
sn=n/2[2.a+(n+1)d]
=n/2[2.11+(n+1)6]
=n/2[22+6n+6]
=n/2[28+6n]
=n[14+3n]
=14n+3n^2