\(-\dfrac{3}{5}\) + \(\dfrac{2}{7}\) : \(\left(\dfrac{4}{5}-x\right)\) = \(\dfrac{1}{3}\)
\(\dfrac{-11}{35}\) : \(\left(\dfrac{4}{5}-x\right)\) = \(\dfrac{1}{3}\)
\(\left(\dfrac{4}{5}-x\right)\) = \(\dfrac{-11}{35}\) : \(\dfrac{1}{3}\)
\(\dfrac{4}{5}-x\) = \(\dfrac{-33}{35}\)
\(x\) = \(\dfrac{4}{5}-\dfrac{-33}{35}\)
\(x=\dfrac{61}{35}\)
\(\dfrac{-3}{5}+\dfrac{2}{7}:\left(\dfrac{4}{5}-x\right)=\dfrac{1}{3}\\ \dfrac{2}{7}:\left(\dfrac{4}{5}-x\right)=\dfrac{1}{3}-\dfrac{-3}{5}\\ \dfrac{4}{5}-x=\dfrac{2}{7}:\dfrac{14}{15}\\ x=\dfrac{4}{5}-\dfrac{15}{49}\\ x=\dfrac{121}{245}\)