Question

Tìm x, biết

\(6x^2-18=0\)

Answer 1

Ta có : \(6x^2-18=0\)

\(\Rightarrow6x^2=18\)

\(\Rightarrow x^2=\dfrac{18}{6}=3\)

\(\Rightarrow x=\pm\sqrt{3}\)

Answer 2

\(6x^2-18x=0\)

\(\Leftrightarrow6x\left(3-x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}6x=0\\3-x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0:6\\x=3-0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\end{matrix}\right.\)

Vậy x=0 và x=3