# For which values of reals $a$ and $x$ this:${x}^{x^{x^{x^…}}}=a$ could be work? [duplicate]

What happens to the W-Function in the expression $${x}^{x^{x^{x^...}}}=a$$ and what values for $$a$$ and $$x$$ they take ? it seems there is a maximum value for $$a$$ that can take and which? Really I can't solved it using W-Function

Note We may avoid triviality case $$x=a=1$$