Answer
If $b$ is between $0$ up to but not including $1$, the function represents exponential decay.
If $b$ is greater than $1$, the function represents exponential growth.
Work Step by Step
$y = a(b)^x$
$a$ = y-intercept
$b$ = Rate of growth/decay
If $b$ is between $0$ up to but not including $1$, the function represents exponential decay.
If $b$ is greater than $1$, the function represents exponential growth.