Đáp án + Giải thích các bước giải:
Bài 7:
`a) x + 1/3 = 2/5 - (-1/3)`
`x + 1/3 = 6/15 - (-5/15)`
`x + 1/3 =11/15`
`x = 11/15 - 1/3`
`x = 11/15 - 5/15`
`x = 6/15 = 2/5`
Vậy `x = 2/5`
`b) 3/7 - x = 1/4 - (-3/5)`
`3/7 - x = 5/20 - (-12/20)`
`3/7 - x = 17/20`
` x = 3/7 - 17/20`
` x = 60/140 - 119/140`
` x = -59/140`
Vậy `x = -59/140`
Bài 8:
`a) -5/12 + 4/37 + 17/12 - 41/37`
`= -5/12 + 17/12 + 4/37 - 41/37`
`= 1 + (-1)`
`= 0`
`b) 1/2 - 43/101 + (-1/3) - 1/6`
`= 1/2 - 1/3 - 1/6 - 43/101`
`= 3/6 - 2/6 - 1/6 - 43/101`
`= 0 - 43/101`
`= -43/101`
