Answer:
y=800(1.15)^x ---> Growth factor: 15%
y=3(0.85)^x ---> Decay factor: 15%
y=2000(4/5)^x --> Decay factor: 20%
y=0.3(0.5)^x ---> Decay factor: 50%
y=1200(1.05)^x Growth factor: 5%
(If b is less than 1, the graph is an exponential decay. If b is more than 1, the graph is an exponential growth.)