Answer:
39062.5
Step-by-step explanation:
-2+-10+-50+-250
-10/2=-250/-50 = 5
sum of the geometric sequence
Sₙ = arⁿ⁻¹ /r-1 a=-2, r = 5
S₈ = -2(5)⁸⁻¹/(5-1) = 2(5⁷)/4 = 2(78125)/4= 78125/2= 39062.5
S₈=39062.5
