[latex] x^{4}+ x^{3}-4x ^{2}-2x+4=0[/latex] Плз решение

[latex]x^4+x^3-4x^2-2x+4=0 \\ (x^4+4)+x(x^2-2)-4x^2=0 \\ (x^4-4x^2+4+4x^2)+x(x^2-2)-4x^2=0 \\ (x^2-2)^2+4x^2+x(x^2-2)-4x^2=0 \\ (x^2-2)^2+x(x^2-2)=0 \\ \frac{(x^2-2)^2}{x^2} + \frac{x^2-2}{x} =0 \\ t= \frac{(x^2-2)}{x} \\ t(t+1)=0 \\ t=-1, t=0 \\ \frac{x^2-2}{x} =-1 \frac{x^2-2}{x} =0 \\ 1) \frac{x^2-2}{x} +1=0 \\ x^2+x-2=0 \\ x=-2, x=1 \\ 2)x^2-2=0, x^2=2 \\ x=- \sqrt{2} ,x= \sqrt{2} \\ Ответ: x=-2, x=- \sqrt{2} , x=1, x= \sqrt{2} [/latex]