[tex]2x^3+x^2-10x-5=0 \\\\x^2(2x+1)-5(2x+1)=0\\\\(x^2-5)(2x+1)=0\\\\x^2-5=0\ \ lub\ \ 2x+1=0\\\\(x-\sqrt{5})(x+\sqrt{5})=0\ \ lub\ \ 2x=-1\\\\x-\sqrt{5}=0\ \ lub\ \ x+\sqrt{5}=0\ \ x=-\frac{1}{2}\\\\x=\sqrt{5} \ \ lub\ \ x=-\sqrt{5} \ \ x=-\frac{1}{2}\\\\x\in\left \{ -\sqrt{5},-\frac{1}{2},\sqrt{5} \right \}[/tex]
