e) $(3 + x)(3 - x) = 0$
$\Leftrightarrow \left[ \begin{array}{l}3 + x = 0\\3 - x = 0\end{array} \right.$
$\Leftrightarrow \left[ \begin{array}{l}x = -3\\x = 3\end{array} \right.$
g) $-3(x + 4)(x - 1) = 0$
$\Leftrightarrow (x + 4)(x - 1) = 0$
$\Leftrightarrow \left[ \begin{array}{l}x + 4 = 0\\x - 1 = 0\end{array} \right.$
$\Leftrightarrow \left[ \begin{array}{l}x = -4\\x = 1\end{array} \right.$
