Question

Fine the sum of the first 8 terms of the arithmetic series 2+7+12+...

Answer 1

156

Explanation:

s8 = n/2 [2t + (n-1)(d)]

= 8/2 [2(2) + (8-1)(5)]

= 4 [4 + (7)(5)]

= 4 (4 + 35)

= 4 (39)

= 156