\(\left(x-\frac{2}{5}\right).\left(x+\frac{3}{7}\right)=0\)
=> \(x-\frac{2}{5}=0\) hoặc \(x+\frac{3}{7}=0\)
=> \(x=\frac{2}{5}\) \(x=\frac{-3}{7}\)
\(\left(x-\frac{2}{5}\right).\left(x+\frac{3}{7}\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-\frac{2}{5}=0\\x+\frac{3}{7}=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0+\frac{2}{5}\\x=0-\frac{3}{7}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{2}{5}\\x=\frac{-3}{7}\end{matrix}\right.\)
Vậy x \(\in\left\{\frac{2}{5};\frac{-3}{7}\right\}\)
Chúc bn học tốt!
