Question

What is 6Σ n=1 [4(-5)^n-1] equal to?

Answer 1

-10416

Explanation:

Answer 2

-10416.

Explanation:

This is a Geometric Series with first term 4 and common ratio -5.

Sum of 6 terms = a1 . (r^6 - 1 )/ ( r - 1)

= 4 *( (-5)^6 - 1) / (-5-1)

= -10416 (answer).