Find an explicit formula for the geometric sequence -8,-40,-200,-1000,..

= - 8

Step-by-step explanation:

The n th term ( explicit formula ) of a geometric sequence is

= a

where a is the first term and r the common ratio

Here a = - 8 and r = - 40 ÷ - 8 = 5, thus

= - 8

an = (-8/5) × 5^n

Step-by-step explanation:

It is Geometric progression with:

first term: -8

common ratio: -40/-8 = 5

an = (-8) × 5^(n-1)

an = (-8/5) × 5^n

12cm

the answer is d