Tìm x biết: x + 1/3 = 2/5 - (-1/3); 2/3.x + 5/7 = 3/10

1. Tìm x:
a) 4/3/5.2/4/23_< x _< 2/3/5:1/6/15
b) -4/1/3-(1/2-1/6)_< x _< -2/3.(1/3-1/2-3/4)
c) x+1/3=2/5-(-1/3)
d) 2/3.x+5/7=3/10
f) 0,5:(x-3/7):1/2=1/1/7