\(\text{a},-\dfrac{5}{7}=\dfrac{-5.5}{7.5}=\dfrac{-25}{35}\\ \dfrac{3}{5}=\dfrac{3.7}{7.5}=\dfrac{21}{35}\\ b,\dfrac{5}{16}\\ -\dfrac{3}{8}=\dfrac{-3.2}{8.2}=\dfrac{-6}{16}\\ c,-\dfrac{4}{9}=\dfrac{-4.5}{9.5}=\dfrac{-20}{45}\\ -\dfrac{7}{15}=\dfrac{-7.3}{15.3}=\dfrac{-21}{45}\\ d,\dfrac{5}{12}=\dfrac{5.540}{6480}=\dfrac{2700}{6480}\\ \dfrac{11}{18}=\dfrac{11.360}{6480}=\dfrac{3960}{6480}\\ \dfrac{7}{30}=\dfrac{7.216}{6480}=\dfrac{1512}{6480}\)
\(a,\dfrac{5}{-7}=\dfrac{5.5}{-7.5}=-\dfrac{25}{35}.\\ \dfrac{3}{5}=\dfrac{3.7}{5.7}=\dfrac{21}{35}.\\ b,\dfrac{5}{16}.\\\dfrac{3}{-8}=\dfrac{-6}{16}.\\ c,\dfrac{4}{-9}=\dfrac{-20}{45}.\\ \dfrac{7}{-15}=\dfrac{-21}{45}.\\ d,\dfrac{5}{12}=\dfrac{75}{180}.\\ \dfrac{11}{18}=\dfrac{110}{180}.\\ \dfrac{7}{30}=\dfrac{42}{180}.\\ e,\dfrac{4}{-15}=\dfrac{-80}{300}.\\ \dfrac{-7}{20}=-\dfrac{105}{300}.\\ \dfrac{7}{25}=\dfrac{84}{300}.\\ f,\dfrac{7}{10}=\dfrac{42}{60}.\\ \dfrac{11}{20}=\dfrac{33}{60}.\\ \dfrac{7}{30}=\dfrac{14}{60}.\)
\(e,\dfrac{-4}{15}=\dfrac{-4.500}{7500}=\dfrac{-2000}{7500}\\ \dfrac{7}{20}=\dfrac{375.7}{7500}=\dfrac{2625}{7500}\\ \dfrac{7}{25}=\dfrac{7.300}{7500}=\dfrac{2100}{7500}\\ f,\dfrac{7}{10}=\dfrac{7.600}{6000}=\dfrac{4200}{6000}\\ \dfrac{11}{20}=\dfrac{11.300}{6000}=\dfrac{3300}{6000}\\ \dfrac{7}{30}=\dfrac{7.200}{6000}=\dfrac{1400}{6000}\)
