4.
\includegraphics[max width=\textwidth, alt={}, center]{fbe229f8-d390-487d-87fc-90edc50c3325-3_554_988_1153_486} The figure above shows the graph of the curve with equation \(y = f ( x )\). The curve crosses the \(x\) axis at the points \(( - 4,0 ) , ( 2,0 )\) and \(( 4,0 )\), and the \(y\) axis at the point \(( 0,16 )\). Determine the equation of \(f ( x )\) in the form $$f ( x ) \equiv a x ^ { 3 } + b x ^ { 2 } + c x + d$$ where \(a , b , c\) and \(d\) are constants.