(x-$\frac{1}{2}$):$\frac{1}{3}$+$\frac{5}{7}$=9$\frac{5}{7}$

`(x-1/2): 1/3 + 5/7 = 9 5/7`

`(x-1/2) : 1/3 = 9 5/7 – 5/7`

`(x-1/2) : 1/3= 9`

`x – 1/2 = 9.1/3`

`x- 1/2= 3`

`x = 3+1/2`

`x= 7/2`

Vậy `x= 7/2`

b) `75% x – x = -1 3/4`

`3/4 x – x = -7/4`

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

`x . (-1/4) = -7/4`

`x= -7/4 : (-1/4)`

`x= -7/4 . (-4)`

`x= 7`

Vậy `x= 7`