Answer:
First one: 5x3(0.75)2t
and fourth one: 0.05x500(0.005)t
Step-by-step explanation:
In order to have an exponencial decay, the rate of the exponencial function needs to be lesser than 1.
The rate is the value between parenthesis, so in the first equation, the rate is 0.75, so this is an exponencial decay.
The second equation has rate = 2.4, so this is not an exponencial decay.
The third equation has rate = 1.04, so this is not an exponencial decay.
The fourth equation has rate = 0.005, so this is an exponencial decay.
