Question

On a coordinate plane, 3 points are plotted. The points are (1, 80), (2, 20), (3, 5).
Which function can be used to represent the graphed geometric sequence?

f(x) = 80(One-fourth) Superscript x minus 1
f(x) = 320(One-fourth) Superscript x minus 1
f(x) = 80(4)x – 1
f(x) = 320(4)x – 1

Answer 1

f(x) = 80(1/4)^(x−1)

Reason: f(1)=80 and the common ratio = 20/80 = 1/4, so the nth-term form is 80*(1/4)^(x−1).