a) \(\frac{1}{3}x^2=\frac{1}{2}x\)
\(\Leftrightarrow\frac{1}{3}x^2-\frac{1}{2}x=0\)
\(\Leftrightarrow x\left(\frac{1}{3}x-\frac{1}{2}\right)=0\)
\(\Leftrightarrow\left[\begin{matrix}x=0\\\frac{1}{3}x-\frac{1}{2}=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\\frac{1}{3}x=\frac{1}{2}\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\x=\frac{3}{2}\end{matrix}\right.\)
Vậy: \(x=0;\frac{3}{2}\)