<=>\(\left(x-3\right)\sqrt{2x^2+2}=x^2-2x-3=\left(x-3\right)\left(x+1\right)\)
<=>x-3 =0 =>x =3
x khác 3
\(\Leftrightarrow\sqrt{\left(2x^2+2\right)}=x+1\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-1\\2x^2+2=\left(x^2+2x+1\right)\end{matrix}\right.\) <=>x^2 -2x+1 =0 => x =1
x={1;3}