From the rules of logarithms, we know that:
log(A) - log(B) = log(A/B)
and thus:
log(1-x) - log(x) = log[(1-x)/x]
Therefore from the question, we know:
log[(1-x)/x] = 1
If we then take both sides of the equation as a power of 10:
(1-x)/x = 10^1
and then multiply both sides through by x:
1-x=10x
Solving for x:
1=11x
x=1/11
We can check our answer by inserting it into the original equation:
log(1-x) - log(x) = log[1-(1/11)] - log[1/11]
and using the rule log(A) - log(B) = log(A/B):
log[1-(1/11)] - log[1/11] = log(10/11)-log(1/11)
= log[(10/11)/(1/11)]
= log(10)
= 1
Thus we know x=1/11