\(\Leftrightarrow x\cdot\dfrac{2}{15}=\dfrac{-3}{4}:\left(3:\dfrac{2}{5}\right)=-\dfrac{3}{4}:\dfrac{15}{2}=\dfrac{-3}{4}\cdot\dfrac{2}{15}=\dfrac{-6}{60}=\dfrac{-1}{10}\)
\(\Leftrightarrow x=\dfrac{-1}{10}:\dfrac{2}{15}=\dfrac{-1}{10}\cdot\dfrac{15}{2}=\dfrac{-15}{20}=\dfrac{-3}{4}\)