Tính tích và hiệu các phân số bằng tính chất phép nhân

a) \(\dfrac{6}{13}.\dfrac{8}{7}.\dfrac{-26}{3}.\dfrac{-7}{8}\)

\(= \left(\dfrac{6}{13}.\dfrac{-26}{3}\right).\left(\dfrac{8}{7}.\dfrac{-7}{8}\right)\)

\(= \dfrac{6.(-26)}{13.3}.\dfrac{8.(-7)}{7.8}\)

\(= (-4).(-1) = 4\)

b) \(\dfrac{6}{5}.\dfrac{3}{13} - \dfrac{6}{5}.\dfrac{16}{13}\)

\(= \dfrac{6}{5}.\left(\dfrac{3}{13} - \dfrac{16}{13}\right)\)

\(= \dfrac{6}{5}.\dfrac{3 - 16}{13}\)

\(= \dfrac{6}{5}.\dfrac{-13}{13}\)

\(= \dfrac{6}{5}.(-1) = \dfrac{-6}{5}\)