If a product is equal to $0,$ at least one of its factors must be $0.$ This means that the equation can be split into new equations. $$\begin{array}{r}x(x+3)(x-2)=0\Rightarrow \begin{array}{l}x=0\\ x+3=0\\ x-2=0\end{array}\end{array}$$ The solutions to the new equations also solve the original equation.