Question

The sum of the series shown in the picture

Answer 1

Partial sum of arithmetic series = n(a1+an)/2
a1=14
an=-280
an=a1+d(n-1), d=2-8=-6
-280=14-6(n-1)
-294=-6n+6
-300 = -6n
n=-300/(-6)=50
partial sum of arithmetic series = 50(14-280)/2=-6650