Question

(x-4)(x+12)=0

Answer 1

(x-4)(x+12)=0

\(\Leftrightarrow\left[{}\begin{matrix}x-4=0\\x+12=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-12\end{matrix}\right.\)

Answer 2

(x-4)(x+12)=0

\(\Rightarrow\left[{}\begin{matrix}x-4=0\\x+12=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=4\\x=-12\end{matrix}\right.\)

Vậy x\(\in\){4; -12}

Answer 3

(x-4)(x+12)=0

⇒ \(\left\{{}\begin{matrix}x+4=0\\x+12=0\end{matrix}\right.\)

⇒ \(\left\{{}\begin{matrix}x=4\\x=-12\end{matrix}\right.\)

Vậy. x∈{4, -12}