Describing Key Features of Functions

Let's start by plotting the three points through which we know the function passes. It crosses the $x$-axis at two places, $x=\text{-}4$ and $x=4.$ Also, its $y$-intercept is $y=16.$

We are also told that the graph has relative maximum at the $y$-intercept. Additionally, it is increasing for $x<0$ and decreasing for $x>0.$ Now, we have enough information to graph the function.

Note, our graph is one of many possible solutions.