\(-\dfrac{10}{21}=\dfrac{5}{3}\cdot\dfrac{-2}{7}\)
\(\dfrac{2}{21}=\dfrac{2}{3}\cdot\dfrac{1}{7}\)
\(\dfrac{8}{15}=\dfrac{2}{3}\cdot\dfrac{4}{5}\)
a) \(-\dfrac{10}{21}=\dfrac{2}{3}.\dfrac{-5}{7}\)
b) \(\dfrac{2}{21}=\dfrac{2}{3}.\dfrac{1}{7}\)
c) \(\dfrac{8}{15}=\dfrac{2}{3}.\dfrac{4}{5}\)