[latex] x^{4}= (x -20)^{2} [/latex]

[latex] x^{4} = (x-20)^{2} \\ x^{4} -(x-20)^{2} = 0 \\ (x^{2} -(x-20))(x^{2}+(x-20)) = 0 \\ (x^{2} - x+20)(x^{2}+x-20) = 0 \\[/latex] [latex]x^{2} - x+20=0[/latex]   или   [latex]x^{2}+x-20= 0 \\[/latex] Первое: [latex]x^{2} - x+20=0 \\ D= 1 - 4*20 < 0 \\ [/latex]   нет решений Второе: [latex]x^{2}+x-20= 0 \\ x_{1}+ x_{1} = -1 \\ x_{1} x_{1} = -20 \\ x_{1}= -5, x_{1}= 4 \\ [/latex] Ответ:  -5 ; 4.

(x²)²-(x-20)²=0 (x²-x+20)(x²+x-20)=0 (x²-x+20)(x+5)(x-4)=0 x₁=-5  x₂=4 Ответ: x₁=-5  x₂=4