Question

fine sum of the followingseries -14 -1 +2 +5....to 21terms​

Answer 1

Answer:

a=-14,d=-14-(-1)

=15

n=21

Sn=n/2(2a+(n+1)d)

substituting the values

S21=21/2(2(-14)+(21+1)15

=21/2(-24+330)

=21/2(306)

=21(153)

=3213