Bài 1:
a) `3/5 + 5/2 `
`= 6/10 + 25/10`
`= 31/10`
b) `7/10 -(7/10 - 1/3) `
`= 7/10 - 7/10 + 1/3`
`= 0 + 1/3`
`= 1/3`
c) `2/7 . 4/5 + 2/7 . 3/5 - 2/7 . 6/5 + (-2/7) . 1/5 + 2/3`
`= 2/7 . 4/5 + 2/7 . 3/5 - 2/7 . 6/5 + 2/7 . (-1/5) + 2/3`
`= 2/7 . (4/5 + 3/5 -6/5 -1/5) + 2/3`
`= 2/7 . 0 + 2/3`
`= 0 + 2/3 `
`= 2/3`
d) `11/13 + (-19/23) + 2/13 - 4/23 + 1/7`
`= (11/13 +2/13) + (-19/23- 4/23) + 1/7`
`= 1 + (-1) + 1/7`
`= 0 + 1/7`
`= 1/7`
e) `3/4 + 25%(3/2 + 1/10) + 3/5`
`= 3/4 + 1/4 . 16/10 + 3/5`
`= 3/4 + 2/5+ 3/5`
`= 3/4 + 1`
`= 7/4`
Bài 2:
a) 1/3x + 1/4 = 1/5`
`=> 1/3x = -1/20`
`=> x = -1/20 : 1/3`
`=> x = -3/20`
b) `1/4 - 2/3x = 2/7`
`=> 2/3x =-1/28`
`=> x = -1/28 : 2/3`
`=> x = -3/56
c) `1/5 (5/2x + 1/3) = 2` `1/3`
`=> 1/5 (5/2x + 1/3) = 7/3`
`=> 5/2x + 1/3= 7/3 : 1/5`
`=> 5/2x + 1/3=35/3`
`=> 5/2x = 34/3`
`=> x = 68/15`
d) `1/2 - 2 (x+1/3) = 1/4`
`=> 2 (x+1/3) = 1/4`
`=> x+1/3 = 1/8`
`=> x = -5/24`
e) `1/3 |x - 1/2| - 1/4 = 1/2`
`=> 1/3 |x - 1/2| = 3/4`
`=> `|x - 1/2| = 9/4`
Th1: `x - 1/2 = 9/4`
`=> x = 11/4`
Th2: `x - 1/2 = -9/4`
`=> x = -7/4`
(Chúc bạn học tốt)