[latex]1) x^{4}-34 x^{2} +225=0 2) x^{4}- 20 x^{2} +64=0[/latex]

[latex]x^{4}-34x^{2}+225=0\\ x^{2}=t\\ t^{2}-34t+225=0\\ t_{1}=25\\ t_{2}=9\\ x^{2}=25\\ x=5;x=-5;\\ x^{2}=9\\ x=3;x=-3; [/latex] Ответ: -3, 3, -5, 5. [latex]x^{4}-20x^{2}+64=0\\ x^{2}=t\\ t^{2}-20t+64=0\\ t_{1}=16\\ t_{2}=4\\ x^{2}=16\\ x=4;x=-4;\\ x^{2}=4\\ x=2;x=-2; [/latex] Ответ: -2, 2, -4, 4.