We can multiply polynomials by using a GRID METHOD
Write one of the polynomials across the top and the other down the left side.
$$ \begin{darray}{|c|c|c|c|}\hline & \color{blue}{2x^2} & \color{blue}{-3x} & \color{blue}{3} \\ \hline \color{blue}{3x} & & & \\ \hline \color{blue}{8} & & & \\ \hline \end{darray} $$Fill in each empty box by multiplying the intersecting terms.
$$ \begin{darray}{|c|c|c|c|}\hline & \color{blue}{2x^2} & \color{blue}{-3x} & \color{blue}{3} \\ \hline \color{blue}{3x} & \color{orangered}{6x^3} & \color{orangered}{-9x^2} & \color{orangered}{9x} \\ \hline \color{blue}{8} & \color{orangered}{16x^2} & \color{orangered}{-24x} & \color{orangered}{24} \\ \hline \end{darray} $$Combine like terms:
$$ 6x^3-9x^2 + 16x^2 + 9x-24x + 24 = \\ 6x^3+7x^2-15x+24 $$