Tìm x biết (2x+3)^2 - (x-1)^2 = 0

* Hướng dẫn giải

$\begin{array}{l}{\left(2\mathrm{x}+3\right)}^2-{\left(\mathrm{x}-1\right)}^2=0\\ \left[\left(2\mathrm{x}+3\right)-\left(\mathrm{x}-1\right)\right].\left[\left(2\mathrm{x}+3\right)+\left(\mathrm{x}-1\right)\right]=0\\ \left(\mathrm{x}+4\right)\left(3\mathrm{x}+2\right)=0\Rightarrow \left[\begin{array}{l}\mathrm{x}+4=0\\ 3\mathrm{x}+2=0\end{array}\right.\Rightarrow \left[\begin{array}{l}\mathrm{x}=-4\\ \mathrm{x}=-\frac{2}{3}\end{array}\right.\end{array}$