Question

sum of first four terms of an arithemetic sequence is 72.sum of first 9 terms is also 72.
find sum of first 5 terms.​

Answer 1

Answer:

24,20,16,12,8

Step-by-step explanation:

Sum of the first 4 terms is 72.

4a+6d=72--->1 eqn

Sum of 1st 9 terms is 72

5a=-30d

-a=6d

Sub in eqn 1

We get d= -4

a =24

Then 1st 5 terms are,

24,20,16,12,8