Tính a) (-3/4 + 2/5) : 3/7 + ( 3/5 + -1/4):3/7 b) 7/8 : (2/9-1/18)+7/8:(1/16-5/12)

0 bình luận về “Tính a) (-3/4 + 2/5) : 3/7 + ( 3/5 + -1/4):3/7 b) 7/8 : (2/9-1/18)+7/8:(1/16-5/12)”

1. a) `(-3/4 + 2/5) : 3/7 + (3/5 + (-1)/4 ) : 3/7`

   `= (-3/4 + 2/5 + 3/5 – 1/4) :3/7`

   `= [ (-3/4 – 1/4) + (2/5 + 3/5)] : 3/7`

   `= ( -1 + 1) :3/7`

   `= 0 : 3/7`

   `= 0`

   b) `7/8 : (2/9 – 1/18) + 7/8 :(1/16 – 5/12)`

   `= 7/8 : (2/9 – 1/18 + 1/16 – 5/12)`

   `= 7/8 : (1/6 + 1/16 – 5/12)`

   `= 7/8 : (1/16 – 1/4)`

   `= 7/8 : (-3)/16`

   `= -14/3`

   Trả lời

2. a)(-3/4 + 2/5) : 3/7 + (3/5 + -1/4) : 3/7

   ⇒[(-3/4 + 2/5) + (3/5 + -1/4)] : 3/7

   ⇒[-3/4 + 2/5 + 3/5 + -1/4] : 3/7

   ⇒[(-3/4 + -1/4)+(2/5 + 3/5)] : 3/7

   ⇒[ -1               +    1]    :3/7

   ⇒           0 : 3/7 = 0

   b)7/8 : (2/9-1/18)+7/8:(1/16-5/12)

   ⇒7/8 : (4/18 – 1/18) + 7/8 : (3/48 – 20/48)

   ⇒ 7/8 : 1/6 + 7/8 : -17/48

   ⇒ 7/8 :(1/6 + -17/48)

   ⇒ 7/8 : -3/16= -14/3

   ~~NGON~~

    

   Trả lời