We can multiply polynomials by using a GRID METHOD
Write one of the polynomials across the top and the other down the left side.
$$ \begin{darray}{|c|c|c|c|}\hline & \color{blue}{x^2} & \color{blue}{3x} & \color{blue}{6} \\ \hline \color{blue}{4x} & & & \\ \hline \color{blue}{-6} & & & \\ \hline \end{darray} $$Fill in each empty box by multiplying the intersecting terms.
$$ \begin{darray}{|c|c|c|c|}\hline & \color{blue}{x^2} & \color{blue}{3x} & \color{blue}{6} \\ \hline \color{blue}{4x} & \color{orangered}{4x^3} & \color{orangered}{12x^2} & \color{orangered}{24x} \\ \hline \color{blue}{-6} & \color{orangered}{-6x^2} & \color{orangered}{-18x} & \color{orangered}{-36} \\ \hline \end{darray} $$Combine like terms:
$$ 4x^3 + 12x^2-6x^2 + 24x-18x-36 = \\ 4x^3+6x^2+6x-36 $$