\(x^3-2x^2-2x-1=0\)
\(\left(x^3-1\right)-\left(2x^2+2x\right)=0\)
\(\left(x-1\right)\left(x^2+x+1\right)-2x\left(x+1\right)=0\)
\(\left(x-1\right)\left(x^2+x+1\right)+2x\left(x-1\right)=0\)
\(\left(x-1\right)\left(x^2+x+1+2x\right)=0\)
\(\left(x-1\right)\left[\left(x+1\right)^2+x\right]=0\)
\(\orbr{\begin{cases}x-1=0\\\left(x+1\right)^2=-x\end{cases}}\)
trường hợp 2 vô lí
\(\Rightarrow x=1\)
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