Question

Tìm x, biết:

( x - 3 ) ( x + 3 )=0

Answer 1

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

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

Vậy....

Answer 2

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

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

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

Vậy ....

Answer 3

(x-3)(x+3)=0

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

<=> \(\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)

Answer 4

(x - 3)(x + 3) = 0

\(\Rightarrow\) x² - 9 = 0

\(\Rightarrow\) x² = 9

\(\Rightarrow\) x = \(\pm\) 3

cách của mik nhanh hơn nên cho mik 2 tik nhé