\(x^3-\frac{4}{25}x=0\)
\(\Rightarrow x\left(x^2-\frac{4}{25}\right)=0\)
\(\Rightarrow x=0\)hoặc \(x^2-\frac{4}{25}=0\)
Nếu \(x^2-\frac{4}{25}=0\)
\(\Rightarrow x^2=0+\frac{4}{25}\)
\(\Rightarrow x^2=\frac{4}{25}\)
=>\(x\in\left\{\frac{-2}{45};\frac{2}{45}\right\}\)
Vậy \(x\in\left\{\frac{-2}{45};\frac{2}{45};0\right\}\)