In Exercises $1-4,$ identify each function as a constant function, linear function, power function, polynomial (state its degree), rational function, algebraic function, trigonometric function, exponential function, or logarithmic function. Remember that some functions can fall into more than one category.
$$
\begin{array}{ll}{\text { a. } f(x)=7-3 x} & {\text { b. } g(x)=\sqrt[5]{x}} \\ {\text { c. } h(x)=\frac{x^{2}-1}{n^{2}+1}} & {\text { d. } r(x)=8^{x}}\end{array}
$$