Answer:
In exponential functions, the variable is that which is in the exponent and whose base is always greater than zero and different from one.
Explanation:
Exponential function is that the variable is in the exponent and whose base is always greater than zero and different from one. These constraints are necessary, since 1 raised to any number results in 1. Thus, instead of exponential, we would be faced with a regular function.
In addition, the basis of the exponential function can not be negative, nor equal to zero, because for some exponents the function would not be defined.