\(x^2-\left(m+2\right)x+m+1=0\)
\(\Delta=m^2\ge0\)
Suy ra pt luôn có hai nghiệm với mọi m
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{m+2-m}{2}=1\\x=\dfrac{m+2+m}{2}=m+1\end{matrix}\right.\)
TH1: \(x_1=1;x_2=m+1\)
Có \(x_1^3=x_2\Leftrightarrow1=m+1\)\(\Leftrightarrow m=0\)
TH2:\(x_1=m+1;x_2=1\)
Có \(x_1^3=x_2\)\(\Leftrightarrow\left(m+1\right)^3=1\)\(\Leftrightarrow m=0\)
Vậy m=0