Question

Tính một cách hợp lí: 1,2×15/4+16/7×-85/8-1,2 × 5 3/4 - 16/7 × -71/8

Answer 1

`1,2×15/4+16/7×-85/8-1,2 × 5 3/4 - 16/7 × -71/8`

`=6/5xx15/4+16/7xx(-85)/8-6/5xx23/4-16/7xx(-71)/8`

`=6/5xx(15/4-23/4)+16/7xx[(-85/8)-(-71/8)]`

`=6/5xx(-8/4)+16/7xx(-14/8)`

`=-32/5`