`~rai~`
\(2x^3+3+3x^2+2x=0\\\Leftrightarrow (2x^3+2x)+(3x^2+3)=0\\\Leftrightarrow 2x(x^2+1)+3(x^2+1)=0\\\Leftrightarrow (2x+3)(x^2+1)=0\\\Leftrightarrow 2x+3=0\quad\text{(vì }x^2+1\ge 1>0\quad\forall x\in\mathbb{R})\\\Leftrightarrow 2x=-3\\\Leftrightarrow x=-\dfrac{3}{2}.\\\text{Vậy x=}-\dfrac{3}{2}.\)