a, \(x+1=\left(x+1\right)^2\)
\(\Leftrightarrow\left(x+1\right)^2-\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x+1-1\right)=0\)
\(\Leftrightarrow x\left(x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
Vậy...
b, \(x^3+x=0\)
\(\Leftrightarrow x\left(x^2+1\right)=0\)
Do \(x^2+1>0\Rightarrow x=0\)
Vậy x = 0
