We can multiply polynomials by using a GRID METHOD
Write one of the polynomials across the top and the other down the left side.
$$ \begin{darray}{|c|c|c|c|}\hline & \color{blue}{x^2} & \color{blue}{-4x} & \color{blue}{16} \\ \hline \color{blue}{x} & & & \\ \hline \color{blue}{-4} & & & \\ \hline \end{darray} $$Fill in each empty box by multiplying the intersecting terms.
$$ \begin{darray}{|c|c|c|c|}\hline & \color{blue}{x^2} & \color{blue}{-4x} & \color{blue}{16} \\ \hline \color{blue}{x} & \color{orangered}{x^3} & \color{orangered}{-4x^2} & \color{orangered}{16x} \\ \hline \color{blue}{-4} & \color{orangered}{-4x^2} & \color{orangered}{16x} & \color{orangered}{-64} \\ \hline \end{darray} $$Combine like terms:
$$ x^3-4x^2-4x^2 + 16x + 16x-64 = \\ x^3-8x^2+32x-64 $$