## Algebra: A Combined Approach (4th Edition)

An exponential function, as explained in the beginning of the section, is a function of the form: $f(x)=b^x$ Where $b$ is greater than 0, $b$ is not 1, and $x$ is a real number. The given function $F(x) = 0.4^{x+1}$ can be expressed as $F(x) = 0.4\times0.4^{x}$. We can see that the function is in the form $f(x)=a\times b^x$ where $b=0.4$. Thus, the function is an exponential function.