$2x³+3x²+3+2x=0$
$⇒(2x³+3x²)+(2x+3)=0$
$⇒x²(2x+3)+(2x+3)=0$
$⇒(x²+1)(2x+3)=0$
$⇒$\(\left[ \begin{array}{l}x²+1=0\\2x+3=0\end{array} \right.\)
$⇒$\(\left[ \begin{array}{l}x²=-1\\2x=-3\end{array} \right.\)
$⇒$\(\left[ \begin{array}{l}x²=-1(vô lí)\\x=\frac{-3}{2}(t/m)\end{array} \right.\)
$vậy$ $x=\frac{-3}{2}$