What is the sum of the first eight terms of the series?

(−800)+(−200)+(−50)+(−12.5)+

round the answer to two decimal places.

−1066.68

−1066.65

−1066.60

−1062.50

-1066.65  to 2 decimal places.

Step-by-step explanation:

(−800)+(−200)+(−50)+(−12.5)+...

This is a Geometric series with common ratio  r =(-200) / ) / (-800)  = 0.25 and first term  a1 = -800.

Sum of n terms = a1 * (1 - r^n) / (1 - r)

Sum of 8 terms = -800 * (1 - 0.25^8) /  (1 - 0.25)

= -800 * 1.333313

= -1066.65.

−1066.65

This is the correct answer! I just took the test

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form

21/58.

hope to be marked brainliest