Tìm x biết: x^2 - 2x + 1 = 9
Tìm x biết: x2 – 2x + 1 = 9.
x2 – 2x + 1 = 9
⇔ (x – 1)2 = 32
⇔ \(\left[ \begin{array}{l}x - 1 = 3\\x - 1 = - 3\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x = 4\\x = - 2\end{array} \right.\).