a: \(\dfrac{2}{-4}=\dfrac{3}{-6};\dfrac{-4}{2}=\dfrac{-6}{3};\dfrac{2}{3}=\dfrac{-4}{-6};\dfrac{2}{-4}=\dfrac{3}{-6}\)
\(\dfrac{2}{3}=\dfrac{-6}{-9};\dfrac{2}{-6}=\dfrac{3}{-9};\dfrac{3}{2}=\dfrac{-9}{-6};\dfrac{-6}{2}=\dfrac{-9}{3}\)
b: \(\dfrac{4}{5}=\dfrac{-8}{-10};\dfrac{4}{-8}=\dfrac{5}{-10};\dfrac{5}{4}=\dfrac{-10}{-8};\dfrac{-8}{4}=\dfrac{-10}{5}\)
\(\dfrac{-2}{5}=\dfrac{4}{-10};\dfrac{-2}{4}=\dfrac{5}{-10};\dfrac{5}{-2}=\dfrac{-10}{4};\dfrac{4}{-2}=\dfrac{-10}{5}\)
c: \(\dfrac{2}{4}=\dfrac{3}{6};\dfrac{2}{3}=\dfrac{4}{6};\dfrac{4}{2}=\dfrac{6}{3};\dfrac{3}{2}=\dfrac{6}{4}\)
d: \(\dfrac{2}{8}=\dfrac{1}{4};\dfrac{2}{1}=\dfrac{8}{4};\dfrac{8}{2}=\dfrac{4}{1};\dfrac{1}{2}=\dfrac{4}{8}\)