(98 ) can someone take a look at this? i'm stumped. (answer choices provided)

what is the fifth term of the geometric sequence?

geometric sequence represented by a graph in quadrant 1 with n on x axis and a sub n on y axis. points at (1,81), (2,9), and (3,1). (graph attached)

hint: an = a1(r)n − 1, where a1 is the first term and r is the common ratio

a5 = 1/81

Step-by-step explanation:

(1,81) (2,9) (3,1)

The sequence goes

81,9,1,

We are multiplying by 1/9 each time

a1 = 81

r= 1/9

an = a1 r^(n-1)

an = 81 * (1/9) ^ (n-1)

The 5th terms

a5 = 81 * (1/9) ^ (5-1)

a5 = 81 * (1/9) ^4

a5 = 81/6561

a5 = 1/81

Step-by-step explanation:

(1, 81), (2, 9), (3, 1) means

the common ratio (r) is: 9 ÷ 81  →  r =  1/9

therefore,

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x