Question

For an A.P. 6,4,2,..., find s10

Answer 1

Hey mate your answer is -30.

using formula
Sn = n/2 [2a +(n-1)d]
where n= 10
a=first term=6
d=common difference=-2.
so,
sn =10/2 [2×6 +(10-1)(-2)]

=5× [12-18]
=5×(-6)= -30 Ans..

i hope it is helpful
plz mark brankiest.

Answer 2

Hey SaknA here

a = 6

d = -2

s10 = n/2 (2a + n-1 d)

      =10/2 (2*6+10-1 *-2)

      = 5 ( 12+ 9*-2 )

      = 5 ( 12-18)

      = 5 * -6

      =-30

∵sn = -30

hope it help