Is the equation A=2100091-120^t a model of exponential growth or decay

I believe this is exponential decay because as the time, t, increases the amount subtracted from the original increases.

Answer: exponential decay

Step-by-step explanation:

the t exponent is on a negative number (120), so as time increases, A would decrease because more and more of t is being subtracted over time. As each unit of time goes by, 120 times the last amount subtracted, would be subtracted from 2100091