Tìm x biết: (x-2)(x+5) - (x-3)(x+3) = 5

* Hướng dẫn giải

$$\begin{gathered} \begin{array}{l}\left(\mathrm{x}-2\right)\left(\mathrm{x}+5\right)-\left(\mathrm{x}-3\right)\left(\mathrm{x}+3\right)=5\\ {\mathrm{x}}^2+3\mathrm{x}-10-{\mathrm{x}}^2+9=5\\ 3\mathrm{x}=6\Rightarrow \mathrm{x}=2\end{array} \\ \mathrm{Vậy}: \mathrm{x}=2 \end{gathered}$$