Toán Lớp 8: tìm x
a) x^2-2x+1 = 0
b) x^3 -4x=0
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Toán Lớp 8: tìm x
a) x^2-2x+1 = 0
b) x^3 -4x=0
Comments ( 2 )
⇔x^2-x-x+1 = 0
⇔x(x-1)-1.(x-1) = 0
⇔(x-1)(x-1) = 0
⇔x-1=0
⇔x=1
⇔x.(x^2-2^2)=0
⇔x.(x-2).(x+2)=0
$⇔\left[\begin{matrix} x=0\\ x-2=0\\x+2=0\end{matrix}\right.$
$⇔\left[\begin{matrix} x=0\\ x=2\\x=-2\end{matrix}\right.$
$⇔\left[\begin{matrix} x=0\\ x=\pm2\end{matrix}\right.$