Tìm x, y thuộc Z biết: a) x(x+6)=0 b) (x−3).(y+7)=0 c) (x−2)(x^2+2)=0

* Hướng dẫn giải

a) $x(x+6)=0\iff \left[\begin{array}{l}x=0\\ x+6=0\end{array}\right.\iff \left[\begin{array}{l}x=0\\ x=-6\end{array}\right.$

Vậy $x=0$ hoặc $x=-6$

b) $(x-3).(y+7)=0\iff \left[\begin{array}{l}x-3=0\\ y+7=0\end{array}\right.\iff \left[\begin{array}{l}x=3\\ y=-7\end{array}\right.$

Vậy x = 3 hoặc x = -7

c) $(x-2)(x^2+2)=0\iff \left[\begin{array}{l}x-2=0\\ x^2+2=0\end{array}\right.\iff \left[\begin{array}{l}x=2\\ x^2=-2\left(L\right)\end{array}\right.$

Vậy x = 2