Bài 1:
a) 3/5+5/3-(-1/2)+1/-4
=3/5+5/3+1/2-1/4
=34/15+1/4
=151/60
b) 1/15+9/10+14/15-1/9-20/10+1/157
= (1/15+14/15)+(9/10-20/10)+1/157-1/9
= 1-11/10-1/9+1/157
=-2893/14130
c) 1/3-3/4-(-3/5)+1/12-2/9-1/36+1/15
= 1/3-3/4+3/5+1/12-2/9-1/36+1/15
=1/12
d)1/1.2+1/2.3+1/4.5+1/5.6+1/6.7
=1/2+1/6+1/20+1/30+1/42
=65/84
bài 2
4/3-(x-1/5) = 3/10+1/2-1/6
4/3-(x-1/5) =19/30
(x-1/5) =4/3-19/30
(x-1/5) =7/10
x =7/10+1/5
x = 9/10
Vậy x = 9/10