Question

Find the sum of the first 10 terms of the given sequence.-3,-15,-75,375,-1875

Answer 1

Answer: -7324218

Step-by-step explanation: This is a geometric series because we can see the sequence is constantly decreasing by multiples of 5.

5 is being multiplied.

Sum of geometric progression formula: $S_{n}=\frac{a(1-r^{n})}{1-r}$

Sn = sum of n terms

a = first term in sequence

r = common ratio/multiple

n = number of terms

Therefore: $S_{10}=\frac{-3(1-5^{10})}{1-5}$ = -7324218

brainliest please :)