You should isolate the term `x^3` to the left side such that:
`x^3 - log(x/3) = 900 => x^3 = 900 + log(x/3)`
This is a transcendental equation, hence, you should perfom graphical method to find the solutions.
You need to draw the graphs of the functions `y = x^3` and `y = log(x/3)` `+ 900` and you need to check if these graphs have common points such that:
Notice that the graphs have no common points, hence, there are no solutions to the given equation.