HI

I'm having trouble finding a solution to a fractional exponent that has an unknown denominator

such as 0.20 = 28.6 x (1/2)^3/x

I can easily determine the solution when the numerator of the fractional exponent is the unknown, but I'm stumped as how to determine the unknown value for a fractional exponent's denominator?

Any references would be most helpful

Thanks in advance.