Giải bài 84 trang 43 - Sách giáo khoa Toán 6 tập 2

Đề bài

   Tính:

Hướng dẫn giải

       Giải: 

    a) \(\dfrac{-5}{6}:\dfrac{3}{13}=\dfrac{-5}{6}.\dfrac{13}{3}=\dfrac{(-5).13}{6.3}=\dfrac{-65}{18};\)

    \(b) \dfrac{-4}{7}:\dfrac{-1}{11}=\dfrac{-4}{7}.\dfrac{11}{-1}=\dfrac{(-4).11}{7.(-1)}=\dfrac{-44}{-7}=\dfrac{44}{7}\)

    \(c) -15:\dfrac{3}{2}=-15.\dfrac{2}{3}=\dfrac{(-15).2}{3}=\dfrac{3.(-5).2}{3}=-10\)

   \(d)\dfrac{9}{5}:\dfrac{-3}{5}=\dfrac{9}{5}.\dfrac{5}{3}=\dfrac{9}{5}.\dfrac{-5}{3}=\dfrac{9.(-5)}{5.3}=\dfrac{3.3.(-5)}{5.3}=-3\)

   \(e) \dfrac{5}{9}:\dfrac{5}{-3}=\dfrac{5}{9}.\dfrac{-3}{5}=\dfrac{5.(-3)}{9.5}=\dfrac{5.(-3)}{3.3.5}=\dfrac{-1}{3};\)

   \(g) 0: \dfrac{-7}{11}=0.\dfrac{11}{-7}=0;\)

   \(h) \dfrac{3}{4}:(-9)=\dfrac{3}{4.(-9)}=\dfrac{3}{4.3.(-3)}=\dfrac{-1}{12}\)