The `nth` term of a series in `A.P.` is `an+b`. Find the sum of the series up to `n `terms.

The nth term of an A.P. is (5n-1). Find the sum of its 'n' terms.

The nth term of an A.P. is (5n-1). Find the sum of its 'n' terms.

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

The nth term of a series is 3^n + 2n ; find the sum of first n terms of the series.

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

The nth term of a series is 3^(n) + 2n , find the sum of first n terms of the series.

The nth term of a series is 3^(n)+2n; find the sum of first n terms of the series.

If the nth term of a series be (2.3^(n-1) + 1) , find the sum of first r terms of the series.

The sum of the first three terms of an A.P. is 9 and the sum of their squares is 35. The sum to first n terms of the series can be

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