a) 3/7.16/15-2/15.-3/7

b)(47/8.9/4-1/2):75/16

c)7/15.-4/9+5/9.7/15

Đáp án:

 

Giải thích các bước giải:

`a,`

`3/7 · 16/15 - 2/15 · \frac{-3}{7}`

`= 3/7 · [16/15 - (-2/15)]`

`= 3/7 · (16/15 + 2/15)`

`= 3/7 · 18/15`

`= 18/35`

`b,`

`(47/8 · 9/4 - 1/2) : 75/16`

`= (423/32 - 1/2) . 16/75`

`= 407/32 · 16/75`

`= 407/150`

`c,`

`7/15 · \frac{-4}{9} + 5/9 · 7/15`

`= 7/15 · (-4/9 + 5/9)`

`= 7/15 · 1/9`

`= 7/135`