Question

Tìm x a) x^2- 2x+1=0 b)x^2 - 9=0

Answer 1

\(x^2-2x+1=0\)

\(\left(x-1\right)^2=0\)

\(\Rightarrow x-1=0\)

\(x=1\)

b)\(x^2-9=0\)

\(\left(x-3\right)\left(x+3\right)=0\)

\(\left\{{}\begin{matrix}x-3=0\\x+3=0\end{matrix}\right.\left\{{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)

Answer 2

Lời giải:

a. $x^2-2x+1=0$

$\Leftrightarrow (x-1)^2=0$

$\Leftrightarrow x-1=0$

$\Leftrightarrow x=1$

b. $x^2-9=0$

$\Leftrightarrow (x-3)(x+3)=0$

$\Leftrightarrow x-3=0$ hoặc $x+3=0$

$\Leftrightarrow x=\pm 3$