Bài 1:
a) -4/7 - 14/56 + 4/7 = -14/56
b) 12/60 + (-1/5 - 2,75) - 0,75
= 0,2 - 1,5 + 2,75 - 0,75
= 0,7
c) -(-31/32 - 7/15) + (-15/32 - 7/15)
= 31/32 + 7/15 - 15/32 - 7/15
= 16/32 = 1/2
d) -5/7 + (4,25 - 2/7) - (1,25 - 3/2)
= -5/7 + 4,25 - 2/7 - 1,25 + 1,5
= -1 + 3 + 1,5
= 3,5

Bài 2:
a) x + 2/9 = 1(1/2) - 7/9
<=> x = 3/2 - 7/9 - 2/9
<=> x = 1/2
b) -13/15 + x = -3/8 - (-4/5)
<=> x = -3/8 + 4/5 + 13/15
<=> x = 31/24
c) 8/13 + (-7/5 - x) = -1/2
<=> -7/5 - x = -29/26
<=> x = -37/130
d) -1(1/7) - [5/3 + (x - 7/3)] = -4/27
<=> 5/3 + (x - 7/3) = -188/189
<=> x - 7/3 = -503/189
<=> x = -62/189