Question

The sum of 6terms of AP .,5,2,-1,... is ____

Answer 1

Answer:

In this AP,

First Term,a1=5

Common Difference,d , a2-a1=-3

Number of terms, n=6

Sum, S= n/2(2a+(n-1)d)

             = 6/2(2*5+(6-1)-3)

             = 3(10-15)

             = -15

             

Explanation: