The exponential functions among the given options are
,
, and
, A, B and E.
How to determine formula?
The task is to determine a formula for an exponential function. An exponential function typically has the form
, where a is a positive constant (the base of the exponential function), and x is the variable.
To go through each option:
a)

This is already in the form of an exponential function. Here, a = e (where e is Euler's number, approximately equal to 2.71828).
b)

This is also an exponential function with a base of 2.
c)

This is not an exponential function. It's a linear function.
d)

This is not an exponential function. It's the natural logarithm function, which is the inverse of the exponential function
.
e)

This is an exponential function with a base of 10.
In summary:
The exponential functions among the given options are
,
, and
.
The other functions,
and
, are not exponential functions.
Complete question:
In exercises 13 and 14, determine a formula for the exponential function f(x)=aˣ.
a) f(x)=eˣ
b) f(x)=2ˣ
c) f(x)=x
d) f(x)=ln(x)
e) f(x)=10ˣ