$ \sqrt{3x^2-5x+1}-\sqrt{x^2-2}=\sqrt{3(x^2-x-1)}-\sqrt{x^2-3x+4} \sqrt{x+3}+\sqrt{3x+1}=2\sqrt{x}+\sqrt{2x+1} x^2+(3-\sqrt{x^2+2})x=1+2\sqrt{x^2+2} $