x = 1
bấm máy tính ra liền mà
\(x^4+4x^2-3x^3-3x+1=0\)
\(x^4-x^3-2x^3+2x^2+2x^2-2x-x+1=0\)
\(\left(x-1\right)\left(x^3-2x^2+2x-1\right)=0\)
\(\left(x-1\right)\left(x^3-x^2-x^2+x+x-1\right)=0\)
\(\left(x-1\right)^2\left(x^2-x+1\right)=0\)
<=> x=1