Answer :

augustaspmokykla

Answer:

-5

Step-by-step explanation:

b1 = +1

b2= -5

b3 = +25

b4 = -125

q = -5  (if u times it -5, u will have every second + or -)

q = [tex]\frac{b2}{b1}[/tex] = -5:1 = -5

sqdancefan

9514 1404 393

Answer:

  the sum of 8 terms of the series is -65104.

Step-by-step explanation:

The first term is 1.

The common ratio is (-5)/(1) = -5.

The sum of 8 terms is ...

  S8 = a1(r^8 -1)/(r -1)

  S8 = 1((-5)^8 -1)/((-5) -1) = 390624/-6 = -65104

The sum of 8 terms is -65104.

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The 8th term is 1·(-5)^(8-1) = -78,125.

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