Bài `1:`
`a, -2/3+ (-11/26)`
`= -52/78 + (-33/78)`
`= -85/78`
`b, -2 - (-5/8)`
`= -16/8 + 5/8`
`= -11/8`
`d, -3 1/2 - (-2 1/4)`
`= -7/2 + 9/4`
`= -14/4 + 9/4`
`= -5/4`
Bài `2:`
`a, x + 1/3 = 2/5 - (-1/3)`
`⇒ x + 1/3 = 11/15`
`⇒ x = 11/15 - 1/3`
`⇒ x = 11/15 - 5/15`
`⇒ x = 6/15`
`b, 3/7 - x = 1/4 - [1/4 - (-3/5)]`
`⇒ 3/7 - x = 1/4 - 17/20`
`⇒ 3/7 - x = 5/20 - 17/20`
`⇒ 3/7 - x = -3/5`
`⇒ x = 3/7 - (-3/5)`
`⇒ x = 36/35`