Question

What is the sum of a 30-term arithmetic sequence where the first term is 73 and the last term is -101?

Answer 1

So the formula is An = a r^(n-1) ?

Answer 2

use the formula

S=(number of terms)/2 (first term+last term)

Answer 3

S=30/2 (73-101)=-420

Answer 4

Thank you..