Tìm số nguyên x biết (x - 4)(x^2 - 25) = 0

* Hướng dẫn giải

$\begin{array}{l}\left(\mathrm{x}-4\right)\left({\mathrm{x}}^2-25\right)=0\\ =>\left[\begin{array}{l}\mathrm{x}-4=0\\ {\mathrm{x}}^2-25=0\end{array}\right.=>\left[\begin{array}{l}\mathrm{x}=4\\ {\mathrm{x}}^2=25\end{array}\right.=>\left[\begin{array}{l}\mathrm{x}=4\\ \mathrm{x}=\pm 5\end{array}\right.\end{array}$