[" 9.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 A.P. is 49 and that of its 17 terms is 289, find the sum of first n terms of the A.P.

The sum of first 7 terms of an A.P. is 49 and that of first 17 terms of it is 289. Find the sum of first 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 first 7 terms of an A.P is 49 and that of its first 17 terms is 289, find the sum of first n terms of the A.P

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

The sum of first 8 terms of an A.P. is 64 and that of first 15 terms is 225. Find the sum of its first 17 terms.

The sum of first 8 terms of an A.P. is 64 and that of first 15 terms is 225. Find the sum of its first 17 terms.

If the sum of the first 9 terms of an A.P. is 81 and that of the first 18 terms is 324, find the sum of its first n terms.