use your usual formulas. You know that
a + a+3d = 2
a^2 + (a+3d)^2 = 20
You will get two solutions, and then you find
8/2 (2a+7d)
The sum of the first and fourth terms of an A.P is 2 and their square is 20.how to find the sum of the first 8 terms?
1 answer