Question

find s3 for the a.p. 3,5,7,9,,.​

Answer 1

Answer:

15

Step-by-step explanation:

a=3,d=2 as 5-3=7-5=9-7=2

s3 =sum of first 3 numbers

s3=n/2(2a+(n-1)d)

=3/2[2(3)+(3-1)2

=3/2[6+4]

=3/2(10)=15.

HOPE THIS HELPS!

Answer 2

1 A Is equal to3 d is equal to 5 -3 e is equal to 2

2 sn is equal to n/2(2a+(n-1) d

3s3 is equal to3/2(2 x3+(3-1) 2

4 3/2(6+4)

5 3/2 x10

6 15