Question

if a4= 4 of an A.P then find the sum of first 7terms of the arithmetic series​

Answer 1

Answer:

28

Step-by-step explanation:

a4 = 4 Let d = common difference.

First 7 terms: 4-3d, 4-2d, 4-d, 4, 4+d, 4+2d, 4+3d

Sum of first 7 terms = 4(7) = 28