The sum of 8 terms of an A.P. is -64 and sum of 17 terms is 289. Find the sum of its 'n' terms.

If the sum of 7 terms of an A.P. is 49 and that of 17 terms is 289, find the sum of n terms.

If the sum of 8 terms of an A.P. is 64 and the sum of 19 terms is 361, find the sum of n terms.

If the sum of 8 terms of an A.P.is 64 and the sum of 19 terms is 361, find the sum of n terms.

If the sum of first term of an A.P is 49 and that of 17 terms is 289. Find the sum of first "n" terms. OR The sum of the third and seyenth terms of an AP is 6 and their product is 8. find the sum of first sixteen terms of the A.P.

If the sum of 7 terms of an A.P.is 49 and that of 17 terms is 289, find the sum of n terms.

If the sum of first 7 terms of an A.P is 49 and that of 17 terms is 289, find the sum of first n terms.

If the sum of first 7 terms of an A.P. is 49 and that of 17 terms is 289, find the sum of first n terms.

If the sum of first 7 terms of an AP is 49 and that of 17 terms is 289, find the sum of first n terms.

If the sum of first 7 terms of an AP is 49 and that of 17 terms is 289, find the sum of first n terms.