#### Answer

Yes

#### Work Step by Step

We are given the function $F(x)=.4^{x+1}$.
In general, exponential functions are written in the form $f(x)=b^{x}$ (where $b\gt0$, $b\ne1$, and $x$ is a real number). In other words, exponential functions consist of a constant that is raised to the power of a variable.
Therefore, the given function is an exponential function, because it consists of the constant .4 raised to the power of the variable term $x+1$.