Question

tính hợp lí 

5/13 . -3/10 . -13/5

Answer 1

\(\dfrac{5}{13}.-\dfrac{3}{10}.-\dfrac{13}{5}\)
\(=\dfrac{5.3.13}{13.10.5}\)
\(=\dfrac{3}{10}\)

Answer 2

\(\dfrac{5}{13}.\dfrac{-3}{10}.\dfrac{-13}{5}\\ =\dfrac{5}{13}.\left(\dfrac{-13}{5}\right).\dfrac{-3}{10}\\ =-1.\dfrac{-3}{10}\\ =\dfrac{3}{10}\)