bài 1 a) 1/2 . ( 4/3+ 2/5) – 3/4 (8/9+16/3) b)1/5:1/10 – 1/3 ( 6/5 – 9/4) c) 1/7:5/14 – 3/2 . (1/6 – 7/12) d)-5/4:(1/4- 7/8)

1 bình luận về “bài 1 a) 1/2 . ( 4/3+ 2/5) – 3/4 (8/9+16/3) b)1/5:1/10 – 1/3 ( 6/5 – 9/4) c) 1/7:5/14 – 3/2 . (1/6 – 7/12) d)-5/4:(1/4- 7/8)”

1. Giải đáp:

    

   Lời giải và giải thích chi tiết:

   a) $\dfrac{1}{2}$.($\dfrac{4}{3}$+$\dfrac{2}{5}$)-$\dfrac{3}{4}$($\dfrac{8}{9}$+$\dfrac{16}{3}$) 

   =$\dfrac{1}{2}$.($\dfrac{20}{15}$+$\dfrac{6}{15}$)-$\dfrac{3}{4}$($\dfrac{8}{9}$+$\dfrac{48}{9}$) 

   =$\dfrac{1}{2}$.$\dfrac{26}{15}$-$\dfrac{3}{4}$.$\dfrac{56}{9}$

   =$\dfrac{13}{15}$-$\dfrac{14}{3}$

   =-$\dfrac{19}{5}$

   b)1/5:1/10 – 1/3 ( 6/5 – 9/4)

      =2-1/3(-21/20)

      =2+7/20

      =47/20

   c)1/7:5/14 – 3/2 . (1/6 – 7/12)

     =2/5-3/2.(-5/12)

     =2/5+5/8

     =41/40

   d)-5/4:(1/4- 7/8) + 3/2 . (1/3 – 5/6)

   =-5/4:(-5/8) + 3/2 . (-1/2)

   =2+(-3/4)

   =5/4

   e)-7/8 : 21/16 – 5/3 . (1/5 – 7/10)

   =-2/3 – 5/3 . (-1/2)

   =-2/3+5/6

   =1/6

   Trả lời