Question

Answer 1

`a)4/5+x=8/10`

`=>x=8/10-4/5`

`=>x=4/5-4/5`

`=>x=0`

Vậy `x=0`

__

`b)1/7-(2/3-x)=-4/7`

`=>2/3-x=1/7-(-4/7)`

`=>2/3-x=1/7+4/7`

`=>2/3-x=5/7`

`=>x=2/3-5/7`

`=>x=14/21-15/21`

`=>x=-1/21`

Vậy `x=-1/21`

Answer 2

14:

a: CB=10-4=6cm

b: CM=BM=6/2=3cm

c: AM=AB-BM=10-3=7cm