Answer:
exponential decay
Step-by-step explanation:
The function is in the form
y = ab^x where a is the initial value and b is the growth or decay rate
If b >1 then it is growth
b < 1 then it is decay
f(x) = 5(2/3)^x
a = 5
b = 2/3
2/3 <1 so it is decay
