Question

Evaluate the summation of 2 times negative 2 to the n minus 1 power, from n equals 1 to 7..

Answer 1

Thank you for posting your question here at brainly. Feel free to ask more questions.  

The best and most correct answer among the choices provided by the question is 86.       
    
Hope my answer would be a great help for you.

Answer 2

Answer:

(D) 86

Step-by-step explanation:

According to the question, the equation will be= \sum_{n=1}^{7}2(-2)^{n-1}.

Now,substituting the values of n from 1 to 7 in the above equation, we have

\sum_{n=1}^{7}2(-2)^{n-1} = $2(-2)^{0} + 2(-2)^{1}+ 2(-2)^{2}+ 2(-2)^{3} + 2(-2)^{4}+ 2(-2)^{5}+ 2(-2)^{6}$

=$2-4+8-16+32-64+128$

=$170-84$

=$86$

Hence, the correct answer will be equal to 86.