To solve this logarithmic equation, we can use the properties of logarithms to combine the terms on the left side of the equation.

Recall that the following logarithmic property holds:

log(a) + log(b) = log(ab)

Using this property, we can rewrite the given equation as:

log((3x * 81x) / 9x) = 3/4

Now simplify the equation:

log(243x^2 / 9x) = 3/4
log(27x) = 3/4

Now we can rewrite the equation in exponential form:

27x = 10^(3/4)

27x = 10^(3/4)
27x = 5.62341

Now, divide both sides by 27 to solve for x:

x = 0.20828

Therefore, the solution to the equation log(3x) - log(9x) + log(81x) = 3/4 is x = 0.20828.