Bài 1:
a) `3/5 + 5/3 + 11/15 = 9/15 + 25/15 + 11/15 `
`= (9 + 25 + 11)/15`
`= 45/15 = 3`
b) `-5/4 . (-3/7) - 5/4 . 17/7`
`= -5/4 (-3/7 + 17/7)`
`= -5/4 . 2`
`= -5/2`
c) `(-1/3)^2 + 60% + 2 8/9 - 8/5`
`= 1/9 + 3/5 + 26/9 - 8/5`
`= (1/9 + 26/9) + (3/5 - 8/5)`
`= 3 - 1 = 2`
Bài 2:
a) `x - 4/3 = 1/6`
`x = 1/6 + 4/3`
`x = 3/2`
Vậy `x = 3/2`.
b) `5,5 - (1/2x + 1/4) = 1/2`
`1/2x + 1/4 = 5,5 - 1/2`
`1/2x + 1/4 = 5`
`1/2x = 5 - 1/4`
`1/2x = 19/4`
`x = 19/4 : 1/2`
`x = 19/2`
Vậy `x = 19/2`.
c) `x - 2/3x = 5/9`
`x (1 - 2/3) = 5/9`
`x . 1/3 = 5/9`
`x = 5/9 : 1/3`
`x = 5/3`
Vậy `x = 5/3`.
