$x^3+3x^2-2x-2=0$
$\to x^3-x^2+4x^2-4x+2x-2=0$
$\to x^2.(x-1)+4x.(x-1)+2(x-1)=0$
$\to (x-1).(x^2+4x+2)=0$
$\to x-1=0$ hoặc $x^2+4x+2=0$
Nếu $x-1=0 \to x=1$
Nếu $x^2+4x+2=0$
$\to (x+2)^2=2$
$\to x +2 = \sqrt[]{2}$ hoặc $x+2=-\sqrt[]{2}$
$\to x = \sqrt[]{2}-2$ hoặc $x=-\sqrt[]{2}-2$