Question

Tính hợp lý

17/31 . -5/19 +  -17/31 . 4/19 

Answer 1

\(=\dfrac{17}{31}\left(-\dfrac{5}{19}-\dfrac{4}{19}\right)=\dfrac{17}{31}.\dfrac{-9}{19}=-\dfrac{153}{589}\)

Answer 2

\(\dfrac{17}{31}.\dfrac{-5}{19}+\dfrac{-17}{31}.\dfrac{4}{19}\\ =\dfrac{17}{31}.\dfrac{-5}{19}-\dfrac{17}{31}.\dfrac{4}{19}\\ =\dfrac{17}{31}\left(\dfrac{-5}{19}-\dfrac{4}{19}\right)\\ =\dfrac{17}{31}.\dfrac{-9}{19}\\ =\dfrac{-153}{589}\)

Answer 3

\(=\dfrac{17}{31}\cdot\dfrac{-5}{19}+\dfrac{17}{31}\cdot\dfrac{-4}{19}\\ =\dfrac{17}{31}\cdot\left(\dfrac{-5}{19}+\dfrac{-4}{19}\right)\\ =\dfrac{17}{31}\cdot\dfrac{-9}{19}=\dfrac{-153}{589}\)