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

Asked by Topperlearning User | 26th Jul, 2017, 01:32: PM

Expert Answer:

Let the A.P. be a, a + d, a + 2d, ......

t3 + t7 = 6

2a + 8d = 6

a + 4d = 3

a = 3 - 4d… (1)

 

(a + 2d) (a + 6d) = 8

Using (1), we get,

(3 - 2d) (3 + 2d) = 8

9 - 4d2 = 8

If

If

Answered by  | 26th Jul, 2017, 03:32: PM