Arithmetic Sum415

Question

Find the arithmetic sum:

 

2-1-4-///-34.

 

Show all step by step work to the solution of the problem. Also give the final solution. Please and Thank You.

Answer 1

It's 2, -1,-4,...-34  THAT'S BETTER!

 

How many terms is that?  2 + (n-1)(-3) = -34

(n-1)(-3) = -36

(n-1) = 12

n = 13.

 

Formula for sum of n terms: (n/2)(a₁ + a_n) = (13/2)(2 + (-34)) = -208.

 

CHECK ALL OF THIS WORK...