giúp e với ạ em cảm ơn

1

a) `0,39 : 0,91 = x : 16 1/3`

` 3/7 = x : 49/3`

` x = 49/3 × 3/7`

`x = 7`

b) `6,88 : 2x =  12 : 27`

` 6,88 : 2x = 4/9`

` 2x = 6,88 : 4/9`

` 2x = 15,48`

`x = 15,48 : 2 = 7,74`

2

a) `x/2 = y/3` suy ra 

`(4x)/8 = (3y)/9 = (4x-3y)/(8-9) = (-2)/(-1) =2`

$\text{x=  2 × 2 = 4 , y = 2 × 3 = 6}$

b) `2x = 5y` suy ra 

`x/5 = y/2  = (x+y)/(5+2) = (-42)/7=-6`

$\text{x = -6 × 5 = -30, y = -6 × 2 = -12}$