Tìm x biết x + 1 = (x+1)^2

* Hướng dẫn giải

$\begin{array}{l}\mathrm{x}+1={\left(\mathrm{x}+1\right)}^2\\ \left(\mathrm{x}+1\right)-{\left(\mathrm{x}+1\right)}^2=0\\ \left(\mathrm{x}+1\right)\left(1-\mathrm{x}-1\right)=0\\ -\mathrm{x}\left(\mathrm{x}+1\right)=0\Rightarrow \left[\begin{array}{l}\mathrm{x}=0\\ \mathrm{x}=-1\end{array}\right.\end{array}$