1/ ĐK: x \(\ge\) 1\(x^2+\left(3-\sqrt{x^2+2}\right)x=1+2\sqrt{x^2+2}\Leftrightarrow\left(3-\sqrt{x^2+2}\right)x+2\left(3-\sqrt{x^2+2}\right)+x^2-7=0\Leftrightarrow\dfrac{7-x^2}{3+\sqrt{x^2+2}}.x+2.\dfrac{7-x^2}{3+\sqrt{x^2+2}}-\left(7-x^2\right)=0\Leftrightarrow\left(7-x^2\right)\left(\dfrac{x}{3+\sqrt{x^2+2}}+\dfrac{2}{3+\sqrt{x^2+2}}-1\right)=0\)