How do we distinguish between exponential growth and exponential decay

For the given problem, we have to distinguish between exponential growth and exponential decay functions.
To distinguish between the given two functions, we will consider the general form of an exponential function which is:
${\displaystyle y\left(t\right)=a\times e^{kt}}$
Where:
y(t) defines the value at time t. The staring or initial value is a and the rate of growth is k. Depending on the sign of rate of growth, we consider that the function is exponential growth or exponential decay.
If k > 0 then the function is exponential growth function.
If k < 0 then the function is exponential decay function.