$(1 - 2x)2 = 4$ (hướng 1)
⇔ $1 - 2x = 4 : 2$
⇔ $1 - 2x = 2$
⇔ $2x = 1 - 2$
⇔ $2x = -1$
⇔ $x = \dfrac{-1}{2}$
Vậy $x = \dfrac{-1}{2}$
$(1 - 2x)^2 = 4$ (hướng 2)
⇔\(\left[ \begin{array}{l}1-2x = 2\\1-2x = -2\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}2x = -1\\2x = 3\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x = \dfrac{-1}{2}\\x=\dfrac{3}{2}\end{array} \right.\)
