Tìm x biết: x(x - 4) = 0
Tìm x biết: x(x – 4) = 0.
x(x – 4) = 0
⇔ \(\left[ \begin{array}{l}x = 0\\x - 4 = 0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x = 0\\x = 4\end{array} \right.\).