Question

find the sum of n terms of AP 5 ,2 ,- 1 ,-4,-7​

Answer 1

Here you go my friend...

Hope it helps you and pls mark it as brainliest

Answer 2

Answer:

by formula : a+(n-1)×d or

Sn=n/2+(2a+(n-1)×d

Step-by-step explanation:

a=5, d=-3, n=?

by solutions we get answers:

n×n=n2

n(1+n)

n(n+1)/2