[tex]1.\\x^4+x^2=12\\x^4+x^2-12=0\\t=x^2\\\\t^2+t-12=0\\\\\Delta=49\\t_1=-4\\t_2=3\\\\x^2=-4\;\; \wedge\;\; x^2= 3\\x\in \emptyset \qquad\;\; x= -\sqrt{3}\;\; \vee \;\;x=\sqrt{3} \\x\in\{-\sqrt{3}, \sqrt{3} \}\\\\2.\\8x^4-6x^2+1=0\\t=x^2\\\\8t^2-6t+1=0\\\Delta=4\\t_1=\frac{1}{4} \\t_2=\frac{1}{2} \\\\x^2=\frac{1}{2} \;\;\wedge\;\; x^2=\frac{1}{4}\\x=\frac{\sqrt{2}}{2}\;\; \vee \;\; x=-\frac{\sqrt{2}}{2} \qquad x=\frac{1}{2}\;\; \vee \;\;x=-\frac{1}{2}\\[/tex]
[tex]x\in \{-\frac{\sqrt{2}}{2}, -\frac{1}{2}, \frac{1}{2}, \frac{\sqrt{2}}{2} \}[/tex]
