the `A.P.` nth term of an `A.P.` is given by `(-4n + 15).` Find the sum of first `20` terms of `A.P.`

If the n^(t h) term of an A.P. is (2n+1), find the sum of first n terms of the A.P.

If the nth term of an A.P. is 4n-1 , find the 30th term and the sum of first 30 terms.

The nth term of an A.P. is 7n-5, find the sum of first 20 terms of the series.

If the nth term of an A.P. is t_(n) =3 -5n , then the sum of the first n terms is ………

The sum of the third and the seventh term of an A.P. is 6 and their product is 8. Find the sum of first sixteen terms of an A.P.

The sum of the third and the seventh terms of an A.P. is 6 and the product is 8. Find the sum of first sixteen terms of the A.P

The sum of the third and the seventh terms of an A.P. is 6 and the product is 8. Find the sum of first sixteen terms of the A.P.

The sum of n terms of an A.P. is 3n^2 + 4n . Find the A.P.

The sum of the third and seventh terms of an A.P is 6 and their product is 8 find the sum of first sixteen terms of the A.P.