`a, 1/2 -(x+1/3)=5/6`
`=> x+1/3 = 1/2 - 5/6`
`=> x+1/3 = 3/6 - 5/6`
`=> x+1/3= -2/6 `
`=>x= -1/3 -1/3`
`=> x= -2/3`
__
`b, 3/4 -(x+1/2)=4/5`
`=> x+1/2 = 3/4-4/5`
`=> x+1/2 = 15/20 - 16/20`
`=> x+1/2 = -1/20`
`=> x=-1/20 -1/2`
`=> x= -1/20 - 10/20`
`=> x= -11/20`
__
`c, 3/35 -(3/5 +x) =2/7`
`=> 3/5 + x=3/35 -2/7`
`=> 3/5 +x= 3/35 - 10/35`
`=> 3/5 +x= -7/35`
`=> x= -1/5 - 3/5`
`=>x= -4/5`
`@` `\text {Ans}`
`\downarrow`
`a)`
`1/2 - (x + 1/3) = 5/6`
`=> x+ 1/3 = 1/2 - 5/6`
`=> x + 1/3 = -1/3`
`=> x = -1/3 - 1/3`
`=>. x = -2/3`
Vậy, `x = -2/3`
`b)`
`3/4 - (x+1/2) = 4/5`
`=> x+1/2 = 3/4 - 4/5`
`=> x + 1/2 = -1/20`
`=> x = -1/20 - 1/2`
`=> x =-11/20`
Vậy, `x = -11/20`
`c)`
`3/35 - (3/5 + x) = 2/7`
`=> 3/5 + x = 3/35 - 2/7`
`=> 3/5 + x = -1/5`
`=> x = -1/5 - 3/5`
`=> x = -4/5`
Vậy,` x = -4/5.`
