Question

the sum of the first n terms of an AP is (3n^2+6n).Find the nth term and the 15th term.

Answer 1

hence the nth term is 6n+ 3 and 15th term is 93I request you to mark this answer as brainliest please please please I have not got even one brainliest answer

Answer 2

Answer:

T 15=93    T n=3+6n

Step-by-step explanation:

na + (0+1+2+3+4.........+n-1)d=3$n^{2}$ +6n

na + (n(n-1)/2)d=3$n^{2}$ +6n

n(a -(d/2))+$n^{2}$ (d/2)=3$n^{2}$ +6n

a-(d/2)=6

d/2=3

d=6

a=9

T 15=9+ 14(6)

=9+84

=93

T n=9 +(n-1)6

3+6n