Tìm x: 2/3.x - 4/6 = 1/8; 2/7 - 8/9x = 2/3

Tìm x:
a, 2/3.x - 4/6 = 1/8
b, 2/7 - 8/9x = 2/3
c, 4/7+5/9:x=1/5
d, 2/5-2/5.x=2/5
e, 2.(x-1/3)=(1/3)^2 +5/9
f, -2/3:(1/2-3x)=5/9