Final answer:
The positive solution for x in the equation fc log_x(81) = 2/3 is 27.
Step-by-step explanation:
To solve the equation fc logx(81) = 2/3, we need to rewrite it in exponential form. Since logarithms can be written as exponentials, we have x^(2/3) = 81. To find the positive solution for x, we can raise both sides of the equation to the power of 3/2, which gives us x = 81^(3/2). Evaluating this expression, we find that the positive solution for x is 27.