a)\(\left(5x-1\right)\left(2x-\frac{1}{3}\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}5x-1=0\\2x-\frac{1}{3}=0\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}5x=1\\2x=\frac{1}{3}\end{array}\right.\) \(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{1}{5}\\x=\frac{1}{6}\end{array}\right.\)