Question

Tìm x

\(3x^2\)+12x=0

Answer 1

\(3x^2+12x=0\Leftrightarrow x\left(3x+12\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\3x+12=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\3x=-12\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-4\end{matrix}\right.\)

Vậy \(S=\left\{0;-4\right\}\).

Answer 2

\(=>\left\{{}\begin{matrix}3x=0\\12x=0\end{matrix}\right.=>\left\{{}\begin{matrix}x=-3\\x=-12\end{matrix}\right.\)