( - 1/90 ) : ( - 1/30 ) - ( - 3/5 )⁻¹ = 1/90 : 1/30 - ( - 5/3 ) = 1/3 - ( - 5/3 ) = 1/3 + 5/3
= ( 1 + 5 ) / 3 = 6/3 = 2;
[tex]\left(-\dfrac{1}{90}\right):\left(-\dfrac{1}{30}\right) - \left(-\dfrac{3}{5}\right)^{-1} =\\ \\\\ = \dfrac{1}{90}\cdot \dfrac{30}{1}-\left(-\dfrac{5}{3}\right) =\dfrac{30}{90}+\dfrac{5}{3} = \dfrac{1}{3}+\dfrac{5}{3}= \dfrac{1+5}{3} =\dfrac{6}{3} = \\ \\ \\ =\boxed{2}[/tex]
