[tex]4x^2\:\left(x^2\:-2\right)\:-2\:=\:5\left(x-1\right)\:\left(x+1\right)\\\\x^4-8x^2-2=5x^2-5\quad\quad\quad /-\left(5x^2-5\right)\\\\4x^4-13x^2+3=0\quad\quad\quad\quad /u=x^2\\\\4u^2-13u+3=0\\\\\boxed{u=3,\:u=\frac{1}{4}}\\\\\\\boxed{x=\sqrt{3},\:x=-\sqrt{3},\:x=\frac{1}{2},\:x=-\frac{1}{2}}[/tex]
