[tex]\log_{2}\log_{\frac{1}{2}}\log_{9}x=0\\
\\ \log_{\frac{1}{2}}\log_{9}x=2^{0}\\
\\ \log_{\frac{1}{2}}\log_{9}x=1\\
\\ \log_{9}x=(\frac{1}{2})^{1}\\
\\ \log_{9}x=\frac{1}{2}\\
\\ x=9^{\frac{1}{2}}\\
\\ x=\sqrt{9}\\
\\ \boxed{x=3}[/tex]
Conditia de existenta: x>0
