Question

The nth term of an A.P. is given by Tn= 4n + 7 .Find the sum of n terms of this A.P.​

Answer 1

Answer:

sum is

$4( \frac{n(n + 1)}{2} ) + 7n \\ = 2 {n}^{2} + 2n + 7n \\ = 2 {n}^{2} + 9n$