Dạng 4. Viết một phân số dưới dạng tích, thương của hai phân số có đáp án

b) $\frac{-10}{21}=\frac{-2}{3}.\frac{5}{7}=\frac{2}{3}.\frac{-5}{7}=\frac{-2}{7}.\frac{5}{3}=\frac{2}{7}.\frac{-5}{3}$

c) $\frac{2}{21}=\frac{1.2}{3.7}=\frac{1}{3}.\frac{2}{7}=\frac{1}{7}.\frac{2}{3}$

d) $\frac{8}{15}=\frac{1}{3}.\frac{8}{5}=\frac{8}{3}.\frac{1}{5}=\frac{2}{3}.\frac{4}{5}=\frac{4}{3}.\frac{2}{5}$

a) $\frac{10}{17}=\frac{2.5}{1.17}=\frac{2}{1}.\frac{5}{17}=\frac{2}{17}.\frac{5}{1}$

b) $\frac{-9}{23}=\frac{3}{1}.\frac{3}{23}=\frac{-3}{1}.\frac{-3}{23}$

c) $\frac{10}{29}=\frac{2.5}{1.29}=\frac{2}{1}.\frac{5}{29}=\frac{2}{29}.\frac{5}{1}$

d) $\frac{-4}{11}=\frac{-2}{1}.\frac{3}{11}=\frac{2}{1}.\frac{-3}{11}=\frac{-3}{1}.\frac{2}{11}=\frac{3}{1}.\frac{-2}{11}$

a) $a)\frac{8}{21}=\frac{1}{3}:\frac{7}{8}=\frac{8}{7}:\frac{3}{1}=\frac{1}{7}:\frac{3}{8}=\frac{2}{3}:\frac{7}{4}=\frac{4}{7}:\frac{3}{2}=\frac{2}{7}:\frac{3}{4}=\frac{4}{3}:\frac{7}{2}$

b) $\frac{8}{21}=\frac{-1}{3}:\frac{7}{8}=\frac{-8}{7}:\frac{-3}{1}=\frac{-1}{7}:\frac{-3}{8}=\frac{-2}{3}:\frac{7}{4}=\frac{-4}{7}:\frac{3}{2}=\frac{-2}{7}:\frac{-3}{4}=\frac{-4}{3}:\frac{-7}{2}$