help with this pls

Question

Is the equation, A = 21,000(1 – 0.12)^t, a model of exponential growth or exponential decay, and what is the percent change per time period?

Answer 1

1-.12 = .88 = 88% decay rate

It's a geometric sequence with a common ratio, r=.88

An= 21,000r^(n-1)

A1 =21,000

A2 =21,000(.88)

A3 =21,000(.88)^2

A4=21,000(.88)^3

A5=21,000(.88)^4

when r<1, it's a decay rate

when r>1 it's a growth rate

Answer 2

(1-0.12) is less than 1. anytime you multiply by less than 1 your result is a smaller number so this is exponential decay

In this specific example 1-.12 =.88 or88%